Well, you have. Kind of...

I've revised my old build with new itemization. I've tweeked the old build for the new patch changes.

The guide is rather plain in appearance. No cool pictures or anything of that nature.

But the content, is invaluable for all/any Alistar players.

Unlike most tanks, Alistar doesn't need a whole lot in terms of defensive items to be an effective tank. His natural HP and ulti are about all he needs to belong on the front lines. The problem with Ali is that his defensive nature makes him unthreatening. Proper itemization is necessary to allow Ali to become a major obstical standing between enemy dps and your squishier teammates.

Play guard dog for the dps/supports. Who ever they focus, you use an ability to peel them and bring down the pain on them as well. All the while, spam your heal to mitigate harass. Do this until one over commits, if one never does you can push them into their tower and whittle the tower down.

If possible you can headbutt carries or supports to locations where they can be focused as well.

Alistar is also a great initiator and chaser.
Protip: Headbutt and Pulverize can be chained to cause an effect similar to Malphite's ultimate. When in range for headbutt, use the ability imediately followed by pulverize. Alistar will lunge forward and pop the enemy up in the air instead of back and deal both skills damage at once. This is a great way to initiate against clumped enemy teams (as pulverize is aoe and will hit all enemies in aoe range) it is also a great way to stop a fleeing opponent from escaping. It also does an incredible amount of burst damage once you have a decent amount of AP- making it excellent for harassing, or bursting down opponents. It is especially effective against extremely squishy but mobile opponents such as Eve and against characters such as Trynd which rely on activating CDs to survive focus.

The need for speed! Alistar needs to have a movement speed advantage over his opponent to be effective. In order to properly position himself for headbutt and to effectively land pulverize Alistar must literally run circles around his target. Investing in boots of swiftness and rylai's crystal scepter early on is of paramount importance.

HP-Ali's ult will not protect you from true damage abilities. This means Lablanc, Olaf, Cho, and ignites are going to tear you apart unless you have stacked hp to some extent. Also, your ultimate needs to be activated. Getting a decent amount of HP to be able to take a few full damage hits without keeling over helps tremendously.

Flash: Flash is a must have for any Alistar. You can flash in and pulverize then aim up a headbutt to punt them to desired location, or you can flash behind them and headbutt them up you lane and pulverize them to stun them in a tower or in an allied gank pack. It of course also is great for escaping when needed (which is necessary occasionally due to most of your survivability being in your ult duration.)

Exhaust: I know that there are several ghost Alistar fanboys out there. Let me put some logic to why you ALWAYS choose exhaust over ghost.

Alistar's goal in life is battlefield control. You protect squishies, and you help focus targets get focused. Being able to ghost and chase after someone pales in comparison to slowing them down so your teammates can kill it in the first place. Also, with the changes to the skill, it is now a very powerful tool to protect squishies against ALL carries (AP included). Simply put, one exhaust wins team fights where ghost will not.

A very important stat to Ali is CDR and as such the utility is very promising. Extra mana and mana regen will help since you will want to use abilities more often and hence burn mana more quickly. Extra movement speed will help since Ali is inherently slow. Improving summoner skills will help both offensively and defensively. Again we want this Ali to be feared and as such getting to AK in the offense tree is highly beneficial.

Alistar is one of the most survivable tanks in the game, hence it is ok not to have defensive masteries.

Your first skill to level is Pulverize. This skill will allow you to farm effectively, is an effective stun/disable and scales really well with AP (1:1). Not to mention it is an AoE ability which is extremely effective against clumped melee.
With the addition of flash this skill is a killer. Flash on to an enemy and pulverize immediately for ganks. A single blow to an equally geared player while laning will do 25%+ (40% is common against the squishier champions) and toss them in the air giving time to line up a headbutt. It is recommended that you get a player to 60% before using flash and completely commiting to a gank as to insure a kill.

Second skill to level is Headbutt. This skill will allow Ali to dash to a fight, is very effective at protecting squishies, scales well with AP (1:1) and can be used to punt enemies into your team's range for focus.

Unbreakable Will is of course your ult and should be kept at max available level. Use this ability when being focused, CC'd, and if you have the mana- i.e. mana for atleast 2 spell rotations and the ult- while ganking. It makes you nearly unkillable. It allows you to tank towers on dives early on and push down towers late game. It is important to play defensively while this is on CD as it is your main source of mitigation. It also breaks crowd control effects and significantly increases your auto attack damage (great for pushing towers).

Triumphant Roar is a great ability. It's cheap and on a low cd so even at a low level it can semi-effectively harass heal. But I recommend only taking one level of it until late game simply because it does not fit the flank-tank-spank play style represented here. When you do hit level 18 your option to support heal with this build also will open up. Also at this point Ali will be nearly unkillable even without his ult because of this ability, high AP, and full CDR.

This is an initiator tank build. It is designed to pick a target, get to that target and move it to a position where it can be focused. After this point the battle is already won. This being said, Ali has all the survivability he needs in his ult. We want him to play a supporting role doing major damage while keeping the enemy team tied up.

Ability Power is incredible for Alistar. Two of Ali's abilities have 100% ratios. Taking advantage of this, especially in the early game, will get your carries fed. A fed carry is what wins the game.

Magic Penetration Marks.
Flat Abiity Power Quints provide almost 15 extra AP.

These are your most important rune purchases. They will make Ali truly formidable in the early game.

Armor seals will help with early game survivability and open the option of jungling earlier and is recommended because little armor is represented in itemization.

Straight CDR glyphs will help get you to the CDR cap and help early game to win lane fights.

We want to feed our carry early on. This is why we stack flat runes over /level.
I will almost always go with flat runes in any build because early game farming is so important to late game success. If you can control your lane, farm, and keep them from farming you will have a much easier time winning that first team fight which often sets the tone for the rest of the game.

Itemization of Alistar is where 99% of players will fail. Most have the mentality of stacking tank items on Ali like you would with most other tank characters. If you do this with Alistar you won't be an asset to the team come mid game. The other team is going to ignore you and you won't be able to hurt them for doing so.

Because of this, Alistar needs to build with offense in mind along with defense. Keep in mind that Alistar has an impressive skill kit. An AoE knock up with 100% AP ratio, a Knock back/lunge with 100% AP ratio, a spammable heal, and an ult that makes you nearly invincible for the duration and gets you out of CC effects. CDR with some mana regen to support it are the first things to focus on- bar none.

Because of this, I start the game with a meki pendent. The mana regen on this item will help you farm, harass, heal, and support you teammate in the lane phase. Don't be afraid to get in and take some harass. You have a hp pot just for level 1- level 3.

(Don't waste too much mana on creeps. Harass the enemy and keep them from getting last hits.
A good way to do this is to headbutt them away from low hp creeps. Pulverize will also work. The enemy will often get frustrated when you do this and put themselves in a position where you can get a first blood. If you effectively harass them enough, often they will become so passive that you and your partner can force them out of the xp zone.)

I first work on boosting Ali's speed.

I get boots of swiftness for the maximum speed value of boots while in combat.

I then upgrade the pendent into a tear of the goddess. This will keep Alistar effectively harassing and give him staying power in team fights. Going oom is one of Alistar's greatest opponents. This will help him be effective.

As soon as possible get a Giant's Belt.

My first major purchase is a crystal scepter. I picked the scepter because of the new passive. This makes Alistar a very effective AoE slow.

I then start building a veil. I build a veil over other defensive options because of a couple reasons:

1) Getting MR over armor first is a good way to go since exhaust will greatly help against phys damage but provides substantially less protection against magic.
2) The best way to kill an Ali is to burst him down so fast that he can't reach his "R" fast enough. A veil will give you that one ability buffer to let you know they intend to kill you and let you get your ult up in time to mitigate the focus.
3) Veil gives HP. HP is great against true damage.
4) Veil gives mana. This allows you to keep a pool large enough to allow you to be fully effective in the team fight if it turns into a long engagement. Also, should the game last long enough it compliments an archangel's very well.

I then build a sunfire cloak. Once you have a cloak, you are pretty hardy. You can withstand a lot of enemy focus and hence they will not focus you even if you present yourself as a target if they have any other targets available. This is why the sunfire really shines above other options. You are going to get up in the enemy carries face and beat the snot out of it and the cloak is going to tick their hp away while you do it. Squishy carries hate the sunfire cloak for this reason.
Additionally, melee heavy teams are going to try and zerg your support and carries. You are going to get up in their faces and disable them. The sunfire is going to punish them for trying to get past you.

I now build a frozen heart. The heart gives a lot of armor and cooldown reduction. It also provides an AS debuff and a good amount of mana. (The mana is very nice for the archangel's staff.)

Alistar is well known as a very good disable tank. He is well known to be a great turret pusher and diver, and be one of the most unkillable champions in the game. It is little known, however, that Alistar is perhaps the single best carry feeders in the game, and that he is also very offensively capable late game if built correctly.

This section will cover how Alistar should be played, both early and late game.

Early game: Alistar the FEEDER

That is, feeding your carry effortless kills.

You will want to lane with a carry who can deal some decent damage early game. The single best laning partner for Alistar to feed is a Miss Fortune. Miss Fortune offers heavy sustained damage and the ability to harass to soften up a target. There are other very good options (Kassadin, Akali, Renekton, Brand, to name a few) but by far the most effective (and undefeated) combination I've found is with MF.

You should shoot for the goal of 1 kill for your carry per flash CD (about 2 minutes).

Allow your carry to get last hits while you keep the enemy from getting last hits of their own. Do this by advancing to your enemy when a friendly minion gets to low hp. They will either not get the last hit and retreat or get the last hit and get pulverized. Do this frequently and heal through the harass they toss your way when you advance on them.
Your carry should also try and harass as much as possible.

The strategy you use to get kills early on will be determined by what you are up against. Most simply, harass which ever one has less defensive capability. Consider shields, self healing, base hp, armor, and mr. If you are up against a support you will, most likely, have to harass the support. Basically, do everything possible to keep them from self repairing. Most champions with self healing do so through life steal/spell vamp. If this is the case, harass them relentlessly if they attempt to hit creeps.
Some champions (Soraka, Vlad, and Sona for example) are difficult to keep from self healing. If your partner has a healing debuff (Katarina, MF) keep it on them as much as possible. It may be necessary to stop harassment and setup and ambush to kill them from full hp.

Ambushes are best setup from bushes or by circling in from behind.

The most basic ambush is to sit in a bush waiting for an enemy to get within flash range. Your partner needs to be notified that ambush is about to happen so he can have all his CDs ready and be in position. If your partner is a ranged champion they do not need to stop last hitting to be ready.

When the enemy you wish to ambush presents itself, flash to it and immediately pulverize. This pops the enemy into the air. Your partner should be unloading abilities on the target as this point. You should get behind it and toss it toward your partner (make sure your partner has enough hp or the target might just jump on your partner and kill him.) If necessary toss exhaust on the target to keep it from running away, killing your partner or lifestealing heavily.

By doing this with a carry you should frequently score kills.

Continue to mess up your opponent's farm and help your carry.
Tip: your heal can screw over enemy last hits by giving them just enough hp to survive, this really frustrates people especially Viegar, Sion, and Nasus who rely on last hits for stats.)

At level 9 your pulverize can kill ranged creeps in one shot. This time period is your most effective time to farm. Use it your full advantage. You can also 1 shot the wrath spawn.

Around level 10 team fights begin to erupt. You are a huge asset to your team. At this point, your carry should be able to kill people very effectively. It's your job to position his targets and to keep him safe from enemy focus by disabling would be attackers.
If your carry is comfortably engaging, killing, and getting out alive the game is over already.

By mid-late game the key damage dealer on either side is pretty well defined. You have two options each team fight.

You will:

1) Protect your carry (do this if the enemy damage dealer is an assassin or if multiple melee are pressuring him. Also, protect your carry from initiator/disable tanks such as Rammus, and Galio)
2) Go after their damage dealer (do this if the target gets within flash range, your carry isn't being pressured (and there are no mias sneaking up on him from behind), or if you've got a numbers advantage. Once you catch the enemy carry pop him up and punt him to where he can be focused.

Building Alistar with an offensive/support nature is honestly the best option. This build boasts a great combination of personal and party utility. I've seen several Ali's build for auras, for survivability, or for damage but in the end, all these builds lack key components which make an affective tank. The team mitigation via CC that this build offers is far greater than passive mitigation achieved by auras. The offensive aura Alistar build lacks personal utility leaving a gimped and underfed tank by mid-late game due to lack of farming potential and has very limited survivability. The straight AP Ali likewise lacks survivability and cannot support teammates as well. Defensively stacked Ali builds can be completely ignored. This build, however,has it all.
Though slightly unconventional, this only serves to give you more of an edge due to them not knowing what you are capable of.