Re: Stuff you like to believe happened in Nolan's series
There are arguments from both sides of the story. I'm of the opinion that the Joker did not win. Batman didn't let him. One of the themes that the second film is putting on the table is that sometimes you have to lie. Keyword here being "sometimes". It's a theme that fits Batman's character as a glove. He does questionable things, but he restricts himself. He set's up his own rules. That's what makes him different. The lie that is made to preserve Harvey's image to the public isn't just a patch. It's a burden Batman sets onto himself, becoming the villain. But there is a side to everything. You can't lie forever. That's what Rises put's on the table. The Ra's hallucination plays on a genuine fear of Bruce, that his mission was pointless that he achieved nothing. But it is more complex than that.
The point the Joker makes is that everyone is a monster, point which is refuted by the people of Gotham, and ultimately by Batman himself. I love the ferries scene, because we have these two factions of people: the common Gothamite in one ferry, and the criminals on the other. Who are the first who reject the chance to blow the other ferry? The criminals. The big guy takes the detonator and throws it away, and his peers don't come up to him filled with anger, to to beat this guy who basically assured their death. No, they accept that is better this way. And on the other side, the common Gothamite, despite voting and agreeing that they will detonate the other boat, they don't. This is perhaps the greatest victory over the Joker on film.
But not everybody is that strong. There is also Harvey Dent.. This is a man who, unlike Gordon, doesn't question Batman's methods. He is eager to support Batman without hesitation. And this is before the Joker makes his move. We can see how he threatens Thomas Schiff. Ultimately, he fails to comprehend entirely what Batman tries to do. That prompts him to his downfall.
Ultimately, not everybody is a monster, there are good people who despite the odds do the good thing. The people Batman defends, and it is because of them that he takes the fall. The conflict of Batman's actions is somewhat literalized with the machine that Batman gives Lucius to make surveillance on Gotham. At the end the machine is destroyed. Batman takes the burden of not only his actions, but more. That's why I think that Batman, despite his apparent downfall, is the one who prevails.
A hero can be anyone. Even a man doing something as simple and reassuring as putting a coat around a young boy's shoulders to let him know that the world hadn't ended.