The Dark Knight is very different. I think that Christopher Nolan, its new director recognised that Burton's version cannot be topped, so he changed tack completely. Where Burton's Batman does not claim to be anything else but an entirely fictitious comic hero, Nolan has transformed Batman to a contemporary political metaphor - the Batman of the 21st century, so to speak. Any similarities with real events and persons are fully intentional, I am sure. And let me say that it is all very well done, with one exception: the transformation of the state prosecutor from Gotham's white knight to a madman is less than authentic. The night is darkest just before dawn - which is scheduled for November 4th.
Incidentally, this movie reminded me of a quote by Max Frisch that I've stumbled on the other day. It's from his New York lectures on journalism, I think, and I cannot recall it verbatim, plus it was in German: You can never describe truth, you can only reinvent it. I think this is quite true, as however much you try to be objective, your description is always a function of your perception and your values. Hence, the most honest (but maybe not the most efficient) way to go about describing the truth is to invent a story that transports clearly what you want to say. In that way, The Dark Knight has quite an unexpected lot of truth.