Hey guys I've mained Cho'Gath for a loong time a while ago but looking at my Ranked stats you can tell I've fallen off my horse. After observing HotshotGG's Cho'Gath games I created a build very similar to his and in my experience with it, it might be my ticket to get back to where I was with Cho'Gath, 80% wins in Normals (very accurate estimate).

Pros:
-NOM NOM NOM (True Damage Nuke)
-Wealth of CC
-Incredible Sustain
-Hard to not focus in team fights (SO BIG!)
-Best Skin Ever

Cons
-Rupture can be predictable to dodge when you're learning Cho'Gath
-Mana problems before getting a Frozen Heart
-Win too much with him that it gets boring :D

Usually on Cho'Gath I take Flash and Teleport for the various things you can do with flash and Cho'Gath's diverse abilities and Teleport becuase it is always good to take in a solo lane. I consider Flash a lock on almost any champion but Teleport can be exchanged for other good choices such as: Exhaust, Ghost, Cleanse, Ignite, and Fortify if you are in a premade.

For runes I go magic penetration marks with everything else as standard defensive runes. These are interchangable as IMO the only lock is Health Quints.

Carnivore, Cho'Gath's passive is one of the greatest sustain abilities in the game. Cho'Gath recovers health + mana every time he kills an enemy unit. This passive encourages Cho'Gath players to farm and that is exactly what he is good at with the use of Vorpal Spikes.

Rupture is a skillshot AoE knockup that slows victims after their knockup by 60%! Put 1 point in it first and max it out last or if you are building Offtank'Gath then max it second as it is your best scaling ability. Learn to hit this and you will never lose a game with Cho'Gath.

Feral Scream is a cone AoE silence that deals decent damage. Max this skill out first as it is an almost guaranteed hit.

Vorpal Spikes is a passive ability that makes all of Cho'Gath's standard attacks deal extra AoE damage in front of Cho'Gath. This is the ability that makes Jungle'Gath possible and makes farming a breeze with Witt's End.

Cho'Gath's signature ability is Feast, his ultimate. This is a close ranged true damage nuke that scales with ability power. If you deal a killing blow with Feast, Cho'Gath gains health permanently (stacks up to 6 times) but if he dies, he loses 1/2 of his stacks (rounded up). His ultimate deals 1,000 true damage to minions and neutral creeps so don't hesitate to gain stacks off of them.

-Lead your Rupture into where the enemy is walking

-While being chased, Rupture to where you are standing and continue running away. Your chaser will be forced to run into the rupture or wait behind it in order to continue chasing

-Make sure to have a few ultimate stacks before engaging a fight - it really makes a difference

-Kill creeps to heal yourself

-Ulting the enemy tank can be extremely effective as it is true damage. You can also take out a carry at 1/2 health with your ultimate

-Feral Scream's silence + Rupture makes escaping and chasing very easy

-"Hide" your carries by standing on top of them when having 6 stacks on your ultimate. Since you become ver big, it makes the enemy's life difficult by not being able to target the carry.

Cho'Gath NEEDS the Frozen Heart. His mana costs are pretty high and his passive does not regenerate his mana very much.

All the other items I included in the build are situational except for boots but I almost always pick up a Witt's End as it helps your early game immensely and a late Guardian Angel can make you invincible.

Witt's End + Vorpal Spikes combine to make farming very easy in the early game. A farmed Cho'Gath is an unkillable one so if you do happen to be dual laning, be fighting for CS with your partner unless he/she is a carry.

Cho'Gath's greatest asset is how amazing he can perform in team fights. His Rupture and Feral Scream are both AoE and his Vorpal Spikes deal extra AoE damage on top of it. Any team choosing Cho'Gath brings a weatlh of crowd control to the table and his Feast is a true damage nuke. Enough said.

Cho'Gath is an elite jungler but I do not play him as such very often. In my opinion, he's a lot better laner than jungler. If you do wish to Jungle Cho'Gath refer to this build, I've used it many times before and will use it many times again.

http://www.mobafire.com/league-of-legends/build/jungle-chogath-how-to-become-a-gentleman-76871

In summary, Cho'Gath is a tank suited for the solo top lane. He has incredible sustain and his ultimate is the strongest damage nuke in the game. I hope you've liked my guide and have fun!