My favorite antagonist, in terms of pure evil, would be:
My favorite antaonist(s), in terms of a pure guilty pleasure, would be:
Ray and Charles Beams from Eureka Seven. Instead of this brain vomit called Ao, Bones should have given us a 26 episode story focused on Ray and Charles adventures, prior to being cursed to meet their doom so a whiny, snot-faced, protagonist could grow as a character.
Actually, there's such a long list of antagonists I love, and it's probably at least ten times longer than the list of protagonists I love.