Ugliest villian ever - The Predator. As Arnold said its "One ugly mother fucker"
Sexiest villian ever - The T-X. Who can forget its arrival through the time displacment equitment.
Second best villian - Darth Vader. Black mask and James Earl Jones voice make for one intimidating villian. His criminal mastermind a imense force powers make him a Hell of a threat. I also like how he is introduced as the most inocent soul imaginable and slowly molds him into a twisted half machine brilliant work for George Lucas.
Best animated villian - Scar. He killed his own brother and let the hyenas ravage the land for his own greed. He had so much hate.