9. The Joker (Heath Ledger) - The Dark Knight
Not the Joker in the comics, because he actually has a back story thanks to The Killing Joke. The Joker in the acclaimed Christopher Nolan film is completely different, a walking mystery. Who really gave him those scars? His father? Did he do it for his wife? Where did he come from? How does he know so much about the mob and about how to rob a bank? We never find out, but there is so much that wasn't explained that makes him so compelling. There's more to him than just a criminal mastermind who doesn't look like he has a plan. There isn't even DNA or fingerprint matches on him. But poof, he appears out of nowhere and turns Gotham City into his own psychotic playground.