Short Version
Loved it, go watch it. Kinda long but that’s not a complaint.

Long Version

Christian Bale did great except of course the weird Batman voice.

The replacement for Katie Holmes wasn’t as good but that character was just weird anyway.

Harvey Dent was awesome.  They didn’t do the multiple personality version like in the animated series, but the transition into Two Face was very elegant.

Heath Ledger was a very good Joker.

There isn’t a teaser for the next villain in the next movie which makes this one feel much more self contained.  In the first one you were sort of led on to anticipate the Joker which was a small cliffhanger leaving you for more.  This one won’t have you waiting in that way.  It was just such a good movie you can’t wait to see whatever is next.

Before Iron Man and Dark Knight came out I was thinking I’d enjoy Iron Man more.  Now after seeing both, I’m leaning towards Dark Knight.  This stems more from not enjoying watching origin stories again to a large degree, but I think Dark Knight really was a killer flick.