The Last Stand. Man, six years later it's still a internet gem.
Yo, what more can I say about this game than others have praised it for? The game is addictive, it's a well-rounded strategy/action game and the most important; it's a zombie shoot-out game. Also, the art is pretty damn good. Sho' nuff.
It's one of the greats, that's all I got to say.