Not Updated For Current Season
This is my first build. Comments or suggestions are always appreciated.
Cho'Gath is a versatile tank/farmer who is capable of chasing, tanking and disrupting during late-game team fights as well as having excellent harassing and laning during the early-game. This build is very strong at running a 2v1 lane as a tower-hugger when you have a jungler, or running a regular lane with strong early-game pushing and harassment.
This is not a carry build. You may get kills and it is possible to carry, but Cho'Gath's primary purpose is to be a huge near-invincible tank that disrupts the enemy team.
I am not a high ELO player. This build has been very effective at my skill-level, but I don't know how it will perform against better skilled players who may be more adept at dodging Rupture.
Try to last-hit minions, but don't take too many hits. If the opposing team is harassing hard, don't be afraid to hug your tower to stay alive. Remember that Cho'Gath's passive restores health and mana for killing minions, plus you're constantly gaining health from your Regrowth Pendant. Taking a couple of hits in order to score minion kills is usually worth it.
If you need to run, it's often a good idea of cast a Rupture under yourself before leaving as opponents will often walk straight into it and get slowed. This is particularly useful when your opponents get into tower range.
If you have a good damage dealer laning with you, you may be able to cast Rupture to score an assist or two.
Once you have enough gold for your Philosopher's Stone and Boots of Speed, or if you need to heal, get back to your lane as soon as you can using Teleport.
By level 6 you will have your Philosopher's Stone which gives you a nice amount of mana and health regeneration. Your job is now to harass and farm with Rupture.
If you can drop an opponent low enough and catch them with Rupture (Slow) you can often score a kill or assist. After slowing with Rupture, cast Ghost and run out, auto-attack and cast Feast for the kill (Or let your laning partner score the kill if they're a carry). Generally it's a good idea to cast Rupture slightly behind your opponents, as most people will back up when you cast it.
Rupture is also an excellent farming skill. Casting Rupture on a group of minions near an enemy will usually make the enemy back away from them. You can then get into range of the minions and kill the group off in 1-2 attacks thanks to Vorpal Spikes. This will also gain you mana back, helping to pay for more Ruptures.
You may find that you are able to push quite easily to the opposing tower. If you do, take the opportunity to auto-attack the tower. When an opposing champion returns to the area, drop a Rupture on the ground beneath you before you start to run. If they try to chase, they will often get hit by the Rupture and be slowed.
Feast is a great skill that can kill any basic minion in 1 shot. Just remember that the cooldown is only 60 seconds so don't be afraid to use it. If you have an opponent who's low on health you may be temped to hold onto Feast until you can get in range to kill them. Just don't get stuck holding Feast. If you can't reach your opponent who's teasing you with their deliciously low health, eat a minion instead. It's not quite as yummy, but you still get a nice health boost.
By level 14 you should have your Boots of Swiftness and one or more pieces of tanky armor. You're now ready to take on your role in teamfights as the tank. You will not usually be targeted first (If you are, great!). Assuming you're not targeted, your job is to spam Feral Scream and Rupture. Rupture should be cast either as a spell to initiate a fight or as a way to help one of your allied champions escape a chase. Feral Scream can be spammed at the other team at any time. It's damage isn't great, but the silence is useful.
The most important thing you can do is to help your team coordinate your efforts. Choose the most dangerous target, hit it with a Rupture and get your team to focus it. Unless you are trying to carry, cast your Feast as soon as possible. You don't want Feast to score the kill, you just want to hit for a big burst of damage so one of your carries can finish the job.
If the teamfight gets crazy and both teams are fighting in a tight cluster, keep yourself in the middle of it and try to soak up as much damage as you can while spamming your Rupture and Feral Scream. Getting knocked into the air, followed by getting hit by Feral Scream as soon as they land can greatly reduces the effectiveness of most enemy AP champions in a teamfight.
As always, the usual things apply during teamfights: Harass with Rupture and try to catch champions that stray from the enemy group. Once your group runs into theirs, focus on the other team's carry. If you're losing, drop a Rupture for your team as they run. You can take a lot of hits - Don't be afraid to drop a Rupture to save a teammate, even if it leaves you with a 2v1 or 3v1 situation. Even in these situations, you have so much health, armor and regeneration that you can usually get out alive by casting Ghost.
Greater Mark of Insight x9
Provides a small amount of additional damage. Your damage output is not great, but these help a tiny bit. These are mostly used only because there is nothing better.
Greater Seal of Resilience[/b] x9
You're a tank. Armor is your friend.
Greater Glyph of Warding x9
You're a tank. Magic resist is also your friend.
Greater Quintessence of Fortitude
Makes you strong in the early-game, letting you lane for longer before you have to run home.
Masteries marked with a * are not very useful and could be changed to others without much consequence.
Resistance (3), Hardiness (3) - Makes you more tanky. Very useful throughout the game.
Evasion (4) - Adds a bit of dodge. You have a lot of armor already, the dodge may not be that useful, but every little bit helps.
Harden Skin (3) - More tankyness.
Veteran's Scars (4) - +48 health = more tanky = great.
Ardor (3)* - I'm still debating whether this is a good choice or not. It marginally improves your attack speed, but you don't have much ability power... Really not too useful. You might be better off skipping this mastery and putting the points into Strength of Spirit for a bit more health regeneration.
Tenacity (1) - Your most important mastery. 4% less damage from everything!
Perseverance (2) - Helps a bit late-game once you have a lot of regeneration.
Haste (1) - lets you chase more effectively and position yourself in team-fights or make a run for it if you get ganked. Very useful.
Spatial Accuracy (1)* - Saves you half a second and lets you teleport a bit more often. Alright, but not essential. If you don't use teleport much, take another point in perseverance.
Awareness (4) - Levels you a bit faster. Nice!
Meditiation (1) - You need as much mana regeneration as you can in the early-game. Useful.
Regrowth Pendant, Healing Potion - These should always be your starting items. They keep you in your lane for a decent amount of time until you have enough gold for your next item(s).
Philosopher's Stone - Your most important early-game item. The health regeneration will keep you in your lane for quite a while and the mana regen will let you harass almost endlessly with Rupture. You will buy this on your first recall. You end up keeping this item for most of the game (Sell it once you run out of slots for items) and the +gold is a nice little perk on top of the amazing regeneration.
Boots of Speed - You will usually buy this on your first recall as well. The added movespeed is nice for scoring last hits on minions.
Boots of Swiftness - Get these as soon as you can. They give you some added mobility for ganking and last-hitting minions, and are very important in keeping yourself in position during team fights and chasing later on in the game.
Force of Nature + Frozen Heart - Makes you really tanky. Can be purchased in either order, depending on the opposing team. Buy based on your opponents in your lane. If you're against a heavy AD or heavy AP team, this may also influence your decision. Depending on the opposing team, you might choose to only buy one or the other. Assuming the opposing team is fairly balanced, buy both items.
Warmog's Armor - Gives you a nice health boost to go with your armor and/or magic resist. Once you have this, you're fairly tough and are definitely ready to tank some towers.
Aegis of the Legion - Build this if you're up against a mixed team of AP and AD. You're often the last one on your team to die since you're so tanky, so you'll be giving a buff to all of your teammates for the duration of the fight.
Guardian Angel - Keeps you alive even longer, makes you more tanky, gives you a nice revive. Again, this is best for mixed AP/AD enemy teams.
Feast > Rupture > Vorpal Spikes > Feral Scream
Feast makes you tanky. Really tanky. Get it as soon as you can and don't be afraid to use it. The health bonus is nice, and it can also be used to score unexpected kills. Since it deals true damage, it will 1-shot most minions, and can deal a solid blow even to really tanky opponents.
Rupture is your most important skill and should be maxed as fast as possible. It allows you to farm, gank, save allies, disrupt teamfights and so much more.
Vorpal Spikes is a great farming skill and also helps you harass early on during laning.
Feral Scream doesn't do much damage and isn't very useful during laning. The silence is good for teamfights later on. Max this last. You might want to put a point into it at level 4 instead of Vorpal Spikes if a silence seems useful to you. As you have limited mana during the early game, it's better to save this for later and just harass with Rupture early on.
Ghost - Essential. Gets you to where you need to be in a teamfight, lets you run away from ganks, chase to kill or to Rupture-slow a fleeing enemy and various other useful tricks.
Teleport - Useful for staying in your lane. Usually a good choice if you're holding down a 2v1 lane due to a jungler on your team.
Flash - Many of the same uses as Ghost. A bit harder to use but still useful.
Clarity - Not recommended, but an option if you want to avoid Philosopher's Stone and have more harassing capabilities early in the game. Late-game mana is usually not a problem.
Fortify - Decent if you're running a lane solo and need to prop up your tower. You're usually better off with Teleport to return to your tower faster.
Ignite - Good for scoring a kill on fleeing enemies. Not great for Cho'Gath unless you're trying to carry.
Exhaust - Good for catching running enemies, or stopping attacks. Ghost does it better. This has some uses in team-fights but I feel that there are better options.
Heal, Revive, Smite, Clairvoyance, Rally, Cleanse - A bunch of stuff that you shouldn't be using ;)
Pros / Cons
Excellent farming capabilities
Very good lane time with strong health and mana regen
Excellent harassment capabilities
Great team-fighter tank
Very tough, hard to gank
Low damage output
Poor early-game laning (Before