^Pft, you two are just jealous. Who wouldn't like pretending you're a mighty wizard conjuring up monsters and spells in a card game ripe with collector's potential? Nothing nerdy about it, I'm sure beefier outdoor types would love it too.
I always liked the Lhurgoyf. He was one of the first supermonsters I ever met in M:tG and it's not that it was kickass which I found interesting, but I love the conceptuals. The Lhurgoyf feeds off corpses so naturally the more creatures there are in the graveyards, the mightier it becomes! I think it was the first card I truly noticed had such a conceptual quality about it.
Besides, I love the quotations they'd put on the cards. "Ach! Hans, run! It's the Lhurgoyf!"
Any other favourites?