Shameless copy/paste of my answer from back in June to the same question:
I'd probably go with the Minion army of the Overlord series. Sure I'd be little more than a pawn for an elder minion, certain to find someone to replace me once I get killed, the heroes thinking my death equates to their victory, thus giving him enough time to Find A Way, as it were, but going around killing, burning, and looting with a small army of brown, red, green, and blue goblin things is pretty good fun.
Alternatively, a swarm of giant, burning, tarantula-clown-wasps that explode on contact with their targets. The stingers, fangs, and seltzer bottles would all be just for show, I would have a colossal swarm of fiery, flying bombs around me at all times. This way, when the hero is pointing his weapon at me while I'm bleeding on the ground (Bad guys never win and all that, a rule I will respect) and asking if I have any last words, I can say "Yes. SWARM, TO ME!!" And blow us both to hell.