Best villain ? Ben Kingsley lol?
Heath Ledger's Joker was the most realistic and the most successful in terms of actually creeping out the audience. He acted a bit different from the animated Joker that everyone's most likely familiar with, but still the same. What I mean by that is that Joker just seemed to want to raise hell for his own entertainment, but when things start to go wrong he instantly changes personalities to an aggressive, murdering maniac. Ledger's Joker stuck a bit closer to the comics, where Joker would challenge Batman again and again to break his rule of not killing anyone. If Batman ever killed Joker, the Joker would still win because his point of everyone being corrupt would be proven right. However, if Batman kept him alive, he would continue to show the Joker that he can't be forced to break his rule and become corrupted, which only fuels the Joker's motivation to try harder next time until he finally gets Batman to snap. Chris Nolan hit this idea from the comics right on the head in The Dark Knight and Heath Ledger made it an epic villain.