Leto did some interesting things with his interpretation, but, his take on it feels more like Black Mask than it does Joker.

While the "Gangster" Joker is a take that has existed in the comics, I still think it takes away from his mythos a bit.

The Joker is a force of nature. A hurricane. He has no interest in hanging out at night clubs or driving fancy cars. Remember when he burned that pile of money in TDK? He exists to prove to EVERYONE that life is chaotic. By the end of The Dark Knight, Ledger's Joker had done just as much damage to the mob as he had done to Batman, Gordon, and Dent. He's not in it to be a criminal, but, to cause destruction and price that life is a joke.

That's why I think Ledger's Joker is probably the best Joker. not just in the movies, but, possibly besting a lot of his comic book incarnations.

Ledger's Joker has no interest in money, or power. he thinks standing for anything is a joke, that's why, in The Dark Knight, his mission is to make Batman, Harvey Dent, and Gordon break the moral and lawful rules they live by. In the interrogation room he tells Batman that he must break his one rule to save Rachel, that's what he wants, to prove to Batman that having rules to live by is a hilarious joke. Joker is willing to die for this. That's why he gives Harvey Dent the gun to shoot him in the hospital, he wants Harvey to cross the line, to make a joke out of the "White Knight" he was trying to be.

AND HE SUCCEEDS. By the end of the movie, he made Harvey Dent kill, and Batman and Gordon had to cover it up and lie. They compromised their ideals.

Ledger's Joker was just as dedicated to his belief in chaos and anarchy as Batman was to justice. I'm not putting down Leto's Joker, but, he felt more like a manic Gangster than an a hurricane of chaos and destruction