This build is oriented around Urgot's ability to completely disrupt and initiate the teamfight game. It focuses on his ability to selectively initiate with squishy/important targets on the enemy team. Most Urgot players will find that they have to harass less and farm more in the early game than they are used to, in order to focus on the mid-late game where Urgot's ult comes into play. This means we'll be building a tanky/support, rather than a harass/damage Urgot.

Marks: We chose mana regen to allow you to spam your abilities to farm iffeciently and still have a decent harass game.

Seals: We chose armor to give him a bigger early-game boost so that you can take less creep damage during the harass, as well as deflecting a lot of physical damage counter-harassment.

Glyphs: We chose MR to maintain defenses against (again) early-game damage from abilities. Pretty simple.

Quints: Another choice to give you a boost in the early-game to allow you to farm well enough to get the tanky items you'll need later.

Pretty much standard 0/9/21 build, with the exception that points were split between the gp/10 mastery and the neutral buff mastery to give you more income for late-game items.

First Buy:

Mana Manipulator: Lane with another mana champ for sustained farming and harassment.

Second Buy:

Boots of Speed: derp.
Kindlegem: More health + CDR, along with the added benefit of more gold income.

Third Buy:

Soul Shroud: Nice health boost, CDR, and mana regen to keep you in lane and able to harass/ult whenever your team needs it. Don't get caught oom!

Fourth Buy:

Negatron Cloak: Nice chunk of MR and builds into either Force of Nature or Banshee's Veil.

Fifth Buy:

Force of Nature: Huge MR, HP regen to recover from fights and initiating, and the movement speed buff doesn't hurt, either.
OR
Banshee's Veil: Get this if your team is getting rocked by AP, not to mention making it a lot easier to escape between the passive and your cleanse.

Late-Game/Boot Choices:
Guardian Angel or, if you really need to shut down an enemy carry, Frozen Heart, will round out your reign of tank supremacy.
For boots, either grab the Mercury's Treads to make sure you lol away safely after sending their Veigar hurtling into your team OR the Lucidity boots to keep your CDR up even higher if, for instance, you can't get blue buff or another team mate needss it more.

Level 1: We know, you'd rather get Acid Hunter. But listen. Wouldn't you rather have a level 1 CC for that first blood rather than a nifty skillshot you'll probably just use to last-hit anyway?

From there on out, it's a pretty standard Urgot build. Prioritize your ult (duh) > Q > W > E

Flash

Cleanse
Makes you better at getting out of the sticky situations your ult usually gets you in, or to avoid CC in order to catch your target.