Hi, this is my first LoL build and I would like to introduce you to my concept of Cho'Gath tank with ****loads of AP in end-game, thus having very high DPS. I'm not experienced player (16 level), although I've played many successful games using this build.

IMPORTANT NOTE:

As the list of items on Mobafire is not up-to-date then some of the items have different statistics.

Overall statistics at 18 level with all items (fully loaded) and 6 stacks of Feast: - unluckily without some of masteries included (low level...)

• Health - 4210
• Mana - 2262
• Health Per 5 sec - 102
• Mana Per 5 Sec - 16
• Armor - 90
• Dodge - 0%
• Magic Resist - 91
• Damage - 195
• Critical Chance - 0%
• Ability Power - 511
• Armor Penetration - 0
• Magic Penetration - 55%
• Movement - 412

Not much has to be said about runes. Just every single rune increases the AP/level and it can be really useful for our mDMG purposes :)

Masteries

• Offense

  - All masteries here are used for one certain reason - to finally assign the point to Archaic Knowledge mastery - 15% of Magic Penetration regarding all of the abilities of Cho are quite useful and defence-ruining to your enemy.

• Defense

  - Not much has to be said here too, we just want to get the Tenacity mastery, increasing armor and other useful defensive stats by the way.

Regrowth Pendant
Item useful in the beginning of the game, slightly increasing your HP Regen on your way to first kill. Included in the Warmog's Armor recipe.
Mercury's Treads
What is our point of interest here is the passive greatly reducing the duration of all de-buffs, so our Cho is definitely more mobile and can run away faster from dangerous situations, same when chasing the running rabbit.
Warmog's Armor
It's extremely important to get this item fast in the beginning of the game, as it's basic stats combined with stack grant us 1370 HP and 45 HP per 5 sec regeneration. That provides you the possiblity to stay muuuch longer on the lane or when trying to kill the opponent.
Tear of the Goddess
It could be wise move to buy this item before the process of building Manamune, as it's stacks grant you lots of Mana, so you can spam with your abilities on minions and farm ****loads of gold.
Void Staff
And that's the first item that gives AP. Not so expensive, quite much AP and again important passive - +40% Magic Penetration. At this early stadium of the game, combined with 15% Mpen from masteries, makes stunning 55% that will definitely crush the Magic Resistance of the enemy.
Manamune
Stats and stacks from Tear of the Goddess combined with 20 DMG and nice 2% of Mana to DMG bonus - quite helpful when attacking and your abilities are on CD.
Rabadon's Deathcap
Time for AP party. No comments needed.
Lich Bane
Further increase of AP and epically useful passive - bonus damage dealt with current number of AP is kind of enormous.

Gives you the chance of fast moving away from troubles, right after usingor chasing the enemy, as Cho has no skill that increases his movement speed.

Beginning:
Cho'gath is not designed to play in the mid, so choose the top or bottom lane. You can also begin your play with killing the wolves in the jungle then proceeding to the lane. You can even achieve First Blood when you get 2 level quickly, and the DMG dealt by Q&E ablities is quite considerable, especially when combined with your lanemate's abilities.

Right after you get the 6th level, you should start gathering Feast stacks. Of course, if you see the guy you can gank and kill using Feast as the finishing skill, then do this, but when there's no opportunity to do this, you should feast random minion/monster, just to get the stack.

Using the Feast skill you can easily get 4/0/0 and earn lots of gold to buy new items faster. The point is to use Rupture (Q) on the enemy (don't forget it is delayed in time), then Feral Scream (W) while the enemy is still slowed down, then switch to normal attack (using Vorpal Spikes of course, the skill is free of charge to use), and further when the cooldows are away re-use your skills and finish the opponent with Feast (R).

Mid-game
At the beginning of this stadium, you should already be equipped with Warmog's Armor, Mercury's Treads and Tear of the Goddess. All of those items will boost your HP and Mana greatly, making you more independent and powerful on the lane. You can gather buffs from Golem and Lizard, that will make you even more powerful. You should be able to bring down the Dragon too.

Using the skill tactics presented before, you should be able to pwn your enemies, chase them and kill even under turrets.

After getting Manamune, Void Staff and at least the part of Rabaddon's Deathcap, your killing possibilites will increase dramatically. Your skill will deal much more damage and killing even 2kHP people solo should end up in 10-15 seconds.

End-game
Now you should have your item build sequence complete, 18 lvl and stats like listed at the beginning of the description. You won't withstand 1v5 madness, but with your high HP level, nice regen, not so bad armor and magic resist, Mpen and finally DMG and AP, you will be possibly the most powerful member of the team, capable of enduring high amounts of damage and dealing high amounts of damage too.

Q-E skills combined would deal about 1,3k mDMG, then attack with Lich Bane passive, should deal another 300+400 DMG. That enables you to gank almost everyone in considerable time. And finally the Feast - another 1k DMG. That's a lot.

I think it would be good idea to leave this chapter for now. I will enter the pros and cons based on your feedback.

Feel free to comment and criticise, as it is my first build here. Good luck in pure pwnage!