Evil? Well, In my own biased opinion (Which, is just an opinion so please don't be offended)
Is probably Fundamentalist Religions or Christianity =l. Christianity mainly because Santa scares me and fundamentalism because...well, do I really need to say why?
One of my favourite antagonists is perhaps Saruman Of Many Colours (Of the White Hand)(P.S I'm Canadian, so my spelling is a tad different.) Sauron began many cliche's, and the idea of him was genius. He was scary because everywhere you could feel his presence. Just imagine the fear, the demoralization your troops would feel as the gaze of the lidless eye is set upon you.
However, I say Saruman, the puppet of Sauron is perhaps my favourite. A corrupt wizard, He symbolized the destruction of symbolism, he symbolized the oratory skills of Hitler, and he was a fine symbol for the power of corruption and greed.
In terms of film I would perhaps say Joker, portrayed by Heath Ledger. He was likeable
From a game I'd probably say Albert Wesker. Albert Wesker was amazing, classy, a genius, and above all...his goals were actually justifiable. He wasn't the antagonist because he was just a douche that wanted to take over the world, he had a view of healing the world by ridding it of humanity - it's biggest cancer.
So there, I contributed a lengthy post for everyone to either read or ignore. (I expect the latter.) OOH and today I got the 'Notable Poster' badge! (Dances) Eh...I'm done.