Firstly, this is way better than all the other Batman films. This has to do with a few key things. Namely, it's excellent Director Christopher Nolan (Memento, Insomnia) and key cast members like Christian Bale, Michael Caine and Liam Neeson. Sadly Katie Holmes doesn't quite carry off her character.
Secondly, it raises a really interesting question.
What do you do with something that is decadent and corrupt? a) destroy it, b) try to save it?