Hello and welcome to my first LoL champion guide. I have been playing Vladimir for a good number of months now, I am in no means a "pro" at him, but i would like to share with the rest of the summoners: my take on "The Crimson Reaper"
When I first bought Vladimir, I couldn't for the life of me figure out why he was tagged as a "tank". I built loads of Ability Power as i would on say Ryze or Katarina, and his passive gave me tons of HP, yet i was still burned through as fast as a Veigar with no bonus HP.
In many solo-que games, everyone picks a carry and locks in, and i am not the best with tanks. Knowing that i would inadvertently let someone die when they expect me to tank better when playing one, i pick Vladimir instead. I decided that since he is tagged as a "tank", i should give it a whirl. After many many games as TankVlad, and never seeing another one out there in the Fields of Justice: I figured I should share some of my knowledge on the subject of Tanking as Vladimir.
I am going to require comment to vote, so please give me feedback before just down or up voting me. This is my first guide so please let me know on what needs improvement.

1/23/2011 - Changed Item Build to add CD Reduction Boots
-Changed Seals to HP/Level
-Changed Masteries

Tanking as Vladimir has it's ups, and it's downs.
Pros:

-Gets a decent amount of kills (and even some of the twilight ladies)
-Incredibly hard to kill
-Can solo lane or 1v2 with ease
-Inadvertently can carry a team of carries that refuse to tank.

Cons

-No offensive capabilities until level 6 at minimum.
-No Crowd Control (besides small slow when standing in his pool)
-Can kill yourself accidentally
-People do not trust your tanking skills and powers at first
-Doesn't need, but very much wants to not share his exp

I bring my standard caster runes to tank as Vlad, since you are going to still want to be useful and deal some damage.
For Marks, I bring 9 Greater Mark of Magic Penetration
For Seals, I bring 9 Greater Seal Of Vitality
For Glyphs, I bring 9 Greater Glyph of Scaling Ability Power
For Quintessences, I bring 3 Greater Quintessence of Magic Penetration
I like to bring these standard caster runes because since Vladimir has no crowd control abilities (such as taunts or stuns), he wont be focused always. Since your not going to be focused, you might as well be able to drop some damage on the people ignoring you.
I bring the Magic Pen Marks and Quints, so that your Transfuse will be able to do a little more damage, letting you last hit minions and harass all the better.
I bring Health/Level Seals mostly because they are just nice, and i wanted to try and move away from the RNG of dodge. They help for early survivability.
I bring Ability Power/Level Glyphs, since this allows you to hit just a wee bit harder, and each point of ability power gives you that much more HP, which combo nice for tanking.
Another good idea, would be to bring Health Quintessences ( Greater Quintessence of Health), and Magic Resist Glyphs ( Greater Glyph of Magic Resist). I choose not to because i primarily itemize for Magic Resistance anyways so i feel that the glyphs would just be a waste.

I used to run 9/21/0 but with my new addition to the CDR boots, i decided to run a 9/0/21 build. I have been using it since then. It works great for me.
In the Offensive tree, first tier, i put one point in Crit chance, as a staple, and 3/3 for the ability power per level.
In the tier 2, i put 4/4 in cool-down reduction, to support our items. In the third tier, i put 1/1 into the 15% magic penetration. This compliments our runes and hitting harder, allowing easier last hitting minions and damage in ganks, on tanks too!
Filling out the utility tree is a bit trickier, since we have to skip all the mana talents.
I put one point into improved ghost, for obvious reasons, then 3/3 in both the health/mana regen talent, and the reduced death, if only to be a staple.
For tier 2, i pop 4/4 into the experience gain, letting you out-level those without it.
For tier 3 i get the money/time talent, and the increased buff duration, not because you will have buffs or because 36g/hour is good, but mostly just staples.
Tier 4, i max out movement. Tier 5 i max the cool-down reduction, and then pop our last point for the less cool-downs on summoner spells.

There are a lot of great choices for summoner spells for Vlad. I prefer to bring along Ignite, and Ghost. I bring Ignite because it helps you land first blood, which is never ever a terrible thing. It combos perfectly with the increased damage your ult allows. And above all other things, It ruins Dr. Mundo, and that is a gorgeous talent to have. Another key thing to note: if you use ghost, and then Sanguine Pool, you are beyond out of there, and tearing out of any fight like a bat out of hell. Something a good vampire should always know how to do.
Other choices i have tried and i feel are viable are:
Cleanse , if you feel like Crowd Control spells are shutting you down. I don't bring this because i usually build Quicksilver Sash, which does the same thing, but better.

Flash, This spell is great for tricking people in the jungle, and getting out of fights, but if you wanna run from a fight, why even get in it in the first place?
I feel like with all the recent workover on Exhaust, Other than the slow, it doesn't bring much to Vlad's table.
If you like a lot of lane/tower coverage than Teleport could be your girl.
If there is some other combo of spells you prefer, than by all means go for it, and let me know about it.

I Always start with Boots and 3 Health Potion
I don't feel like any of the Doran's Items are good on him, other than the shield, but i like to grab an item that actually goes into something.
I try to not go back to base until i have accumulated 1600 gold ish. After getting a kill or dying once you have that much, I head back, and get Spirit Visage. This helps a lot by giving cooldown reduction, so you can Transfuse all the faster. It also gives you 20% increased healing, so your Transfuse just helps you out more with the return, plus you get that magic resist, which never hurts.
You will next want to finish your boots. The new Ionian Boots of Lucidity are amazing. Combo'd with the CDR from your spirit visage, and masteries, you should be at 36% which is almost capped. Your Transfusion should be on a 1.92 second CD, and maxed it goes to 1.8 Seconds, so you should be heavily set on CDR.
If the team is heavily laden with Auto-attackers, then get Ninja Tabi. One other thing to keep in mind, is that if the enemy team is full of disables (IE: Jax, Blitzcrank, Anivia, Sion, and Taric ) you should probably take the smarter route and invest in Mercury Treads.

One other honorable mention for boots is Mobility Boots, If only because it instantly removes you from combat when you drop into your Sanguine Pool, thus bringing you to move speed 5. That combo'd with Ghost, will almost insure you are out of combat and behind 3 towers.

I don't see many people build this, but the next item on my list is Quicksilver Sash. Vlad is very susceptible to being disabled, and dying during that disable. Sure you can Sanguine Pool once, but after that you are wide open. The Magic resist helps too.
After those three items, you need to look at the opposing team, if they have only one caster: think about skipping this item. Usually i build a Force of Nature. The unique passive on this regenerates .35% of your health every second and an extra 40hp/5seconds , and even more because you have 20% increased healing on you. The other nifty feature is that it boots with a ridiculous amount of magic resist, so with this, casters such as Lux, Karthus, Malzahar, viegar, so on so forth, will do nothing to you anymore.
Next on the list, i would have to say, would be Warmog's Armor. This green giant here gives you quite a great amount of health. Health gives you ability power which is always good. Nothing else to explain i don't think. Oh and the health regeneration, plus increased from the Spirit Visage.
For your last item, its kinda up to you. Most games i find myself looking to get Guardian Angel. Its got magic resistance, its got armor, and when you die, you come back. What more do you need? Plus it keeps your score nice and pretty.
If you are facing a team that made you get the Ninja Tabi, and someone like Tristana, or Miss Fortune is tearing you apart, then go ahead and hook yourself up with the cheap wonder know as Thornmail.
Another Armor item that is worth thinking about is Sunfire Aegis.
The last item i would recommend for your last item slot is Rylais Crystal Scepter. This little item seems like it was made for our Crimson Impaler. Its got Health that is converted into ability power. Its got ability power that is converted into health. And it makes all of your spells slow people down, which could be just what your team needed to catch that annoying Zilean or Nidalee escape artist.

When you start the game, it would be most beneficial for you to be middle lane or solo. If your team has a jungler, than you should gladly go face off against 2 people and let someone less powerful take the 1v1 lane. Either way though you are going to want solo, so let them know that, because it will help you reach level 9 quicker (since that's when transfuse can be on its shortest cooldown outside of items) and to get as much farm as possible, since if your team wants you to tank, you better get the items to do that!
Feel free to go gank other lanes when your middle, if you can sneak in a lane, with a good ult, then a slow from your pool, either you or a teammate should be guaranteed a kill.

When you are laning and having battles, there is always the tricky subject of skill sequence or order/rotation.
While laning i prefer to harass with Transfusion, Pop your summoner spell Ghost, Run into the enemy, use your Ultimate, followed by tides of blood, followed by Sanguine Pool, once out of the pool, use your Tides of Blood and transfusion.
So for simplicity: R>Q>E>W>E>Q>E>Q>E>W>Q>E>Q>E>Q>E>Q

I just added this for a place to post a few screen shots of this build in work. Sorry for the terrible quality on some of them.
Images Uploaded by www.imgur.com