Heath ledger played The Joker so well. He obviously did his homework on the character, because he got that the joker is not insane but has a "super-sanity" and got how The joker views the world. About the only thing that the movie did not show that is a trademark of The Joker is that he knows when he is in a comic book or animated series. Also I love how Christian Bale has been able to combine Bruce Wayne and Batman. Usually the actor for Bruce/ Batman either plays a good Bruce and not Batman or a good Batman and not a good Bruce.