This ambitious film represents for me a perfect storm of certain elements coming together:
1) Wally Pfister's cinematography: the widescreen formatting and the use of the IMAX camera creates a new sense of cinematic engagement on the big screen- Gotham feels tangible and the action feels epic.

2) It's an entertaining pop culture study into the psychology of evil: The construction of the Joker character is a revelation- the writers had the good sense to jettison a pathetic backstory for the villain and instead turned him into an intriguing enigma of evil who deceptively plays by a very specific set of rules despite the chaos he constantly creates on his wake- The Joker simply uses existing human deficiencies and Batman's incorrupability to bring Gotham to its knees. The lack of a backstory for the character in itselffalse makes the character very unnerving- how do you destroy an enemy you don't know or can never really know???

3) The Dark Knight is a master class in escalation- all the different stories and themes seem to flow together towards the end and it feels like Nolan is always in total control.

4) Has one of the best endings ever : because its outcome is completely predicated by a lie to cover the crimes of Harvey Dent. This serves two great purposes: 1) The plot point opens up the story for further exploration: Can Gotham ever gaze upon its true face and move in a positive direction??? 2) helps the film stand on its own as a meditation on the inherent complications of functional heroism in an imperfect world.