I like the Worldgorger Dragon because it has the ultimate "Fatty Threat" aura on it. The Dragon states "I'm big enough to win this game by myself and I'll prove it!!!!" Of course, any removal can take care of it, but that's the same with any creature. I loved this creature with it's "Infinite Mana Combo/Draw the game into forever-land" engine generated with Animate Dead.
Anyway, with its appeal of being the only fatty you need to win the game, it got my nomination.
Ransac, cpa trash man