Eurobricks' member 'def' has designed a series of minifigures that really should be seen.
Largely divided into three themes, Steam Land, Hotel, and Mythology. Each one has some nice design elements.
My favorite is the Medusa figure pictured here. I thought something similar, but with a snake tail instead of legs would be quite nice for the Collectible Minifigures Series 3. A perfect compliment to The Zombie, Witch, and Vampire.
See the rest of def's designs on the Eurobricks forums.