The Dark Knight was absolutely awesome - go see it, asap. The Joker and his reasoning actually make sense by the end (at least to me - that's probably not healthy). Good back-and-forths regarding heroism, right vs wrong, good vs evil, nature of humanity, things like that. I expect I'll be seeing it a second time in theaters, and owning it when it hits DVD. More discussion will ensue when more people have seen it.
To help, no there's nothing after the credits. We waited.
However, you absolutely WILL want to catch the previews, just for the Watchmen trailer. Trust me,
Youtube cannot do it justice. Also, 1000 karma and a little tag or something for the first person to give me the full (from the graphic novel / comic book) version of the quote at the end, as well as who says it.
For the other 99% of you who haven't read it, GO GET IT. It's like $20 at Borders (yes, the full thing), $14 or so on Amazon. It's an absolutely fantastic read - each character has tons of depth, the story's interesting and has a helluva twist at the end (so don't turn to the back when thumbing through it), and the discussion between _____________ and Dr. Malcom is a very poignant examination of the morality of humanity in general (and thus makes a good follow-up to TDK).
"Stood in firelight, sweltering. Bloodstain on chest like map of violent new continent. Felt cleansed. Felt dark planet turn under my feet and knew what cats know that makes them scream like babies in the night. Looked at sky through smoke heavy with human fat and God was not there. The cold, suffocating dark goes on forever, and we are alone. Live our lives, lacking anything better to do. Devise reason later. Born from oblivion, bear children, hell-bound as ourselves, go into oblivion. There is nothing else. Existence is random. Has no pattern save what we imagine after staring at it for too long. No meaning save what we choose to impose. This rudderless world is not shaped by vague metaphysical forces. It is not God who kills the children, not fate that butchers them or destiny that feeds them to the dogs. It's us. Only us."
I'm also taking the trailer and gonna try to make avatars out of the characters. First come first serve if you have a favorite character / one you like, but you have to be able to tell me who it is (Wikipedia is sufficient for that one - bonus if you can explain why you like them). I'm gonna have to watch the trailer a few more times, but I have two in mind myself, so we'll see. I might can also make avatars directly from the comic book itself, if you prefer.
e: And since I know y'all are wondering, yes, I had to get some moist towlettes and go to the bathroom for a few minutes after the trailer. The movie didn't quite hit me with the same rush, so I was fine going home. The movie has its own, but much more subtle, appeal - you watch it and come away with a very satisfied feeling, like the feel of a cigarette after really good sex.