Batman Begins, and Bane is the man who broke the bat in The Dark Knight Rises, but in retrospect, they feel more like obstacles to overcome. There's was never any question that Batman would rise to the challenge of facing them; he would not give up.
Meanwhile, in The Dark Knight (2008), the Joker makes Batman blink. Their first big fight concludes when the Joker stands in the middle of road against the oncoming Batpod, refusing to move, and Batman swerves and crashes, saved only by the presence of soon-to-be Police Commissioner Gordon (Gary Oldman). Ra's and Bane are both strategists, but Joker is insane enough to die to prove a point; he has no agenda or goal other than chaos, the complete antithesis to Batman, who is about order and justice. When Batman and Joker have a face-to-face discussion in the police interrogation room, the Clown Prince of Crime gets inside the Dark Knight's head, taunting with the knowledge he has no weapons or threats that would work against him. This monster shakes Batman to his core to the point he at one point is willing to give up the mantle, lest he go down a dark path to stop him.
When you compare all three Nolan Batman movies, it becomes apparent the central running theme is symbols and the messages they inspire. In Batman Begins, Bruce Wayne becomes Batman for two reasons: to frighten the city's criminal element and show the people of Gotham there is reason to hope. In The Dark Knight Rises, the series concludes when Batman inspires the police to literally take back the city from crime after a period in which Batman's absence left a void and another symbol was torn down.
The Dark Knight begins (after an opening bank heist by Joker in which he kills all his accomplices) with Batman encountering copycat Batmen while wrapping up a loose end from the previous movie. These vigilantes use guns and wear hockey pads, not exactly what Bruce Wayne meant when he said he wanted to inspire people. Meanwhile, the Joker is the criminal response to Batman, the escalation, the evil the Bat inspired (albeit unintentionally). His plan is all about tearing down symbols of hope and justice. To him, life is a cruel joke, and he wants to expose everyone as being as evil and twisted as he is. By unmasking Batman, he'll reveal him to be fake, and by going after Harvey Dent, Gotham's "white knight," the clean, uncorrupted hero Batman could never be, the Joker can destroy the people's hope and soul.
The downfall of Harvey Dent and his transformation into the scarred Two-Face is well known to comic book fans, and it's handled much better here than it was in Batman Forever. Unlike Tommy Lee Jones, Aaron Eckhart is not a cackling, goofy Joker-clone but a pained and tortured soul who becomes twisted. We witness how good and just he was and how he believed in never selling out, which makes it all the more tragic when he becomes warped and vengeful. He flips the coin, and he sticks with the outcome no matter what.
For the first two hours, The Dark Knight is arguably the best of the Nolan Batman movies, but it grows cumbersome in the last half-hour. I said in my Dark Knight Rises review the third entry probably has the most plot holes and contrivances, but The Dark Knight likely has the one of the most unlikely developments. Near the end, Joker rigs two ferries - one with Gotham citizens, the other with prisoners- to blow up. Each boat has the detonator to the other, and Joker will blow them both up if neither makes a choice. This is a great setup and so like the Joker (although the choice aspect is traditionally Two-Face's M.O.), but the resolution and how it plays out struck me as very unlikely. Thematically, you could call this the big turning point in the series for the city itself when this sampling of people on boats (appropriately named Spirit and Liberty) make the choice they do, but narrative-wise, it strains plausibility.
Another great Joker scheme ruined by a poor payoff is when he takes hostages and dresses them as clowns with guns duct-taped to their hands while the real henchmen are dressed as doctors and nurses. How does Batman respond to this development? By alerting Gordon, warning the approaching SWAT teams, or some other way of passing on this information? No, he beats up the SWAT guys and leaves several dangling off the side of the building while there are still armed threats around. I guess Batman just likes beating people up.
So, that's The Dark Knight, and yes, Heath Ledger's Oscar-winning turn as the Joker remains brilliant. It's worth watching just for his performance, although the movie does have other attributes going for it as well as some frustrations. Nolan must be applauded for considering the larger, thematic picture of the series and tying everything together, but some details and changes ring false.