Oh god. I'm jumping with the band wagon here. I love Joker. Jack Nicholson's Joker, Mark Hamill's Joker, and Heath Leger's Joker. THE CHARACTER IS JUST AWESOME. Now, what did Heath bring to the table. Since this was "The Dark Knight" and not the original "Batman" Joker was depicted as a much more twisted character than he already is (and if you've seen Mark Hamill's Joker, you'll see that's he's already one messed up loon.) And you know what? Heath delivered. Joker was much more twisted. He was so sick it was compelling. Hands down one of the best villains I know.
I would've loved Bane. Initially, I was hooked, until the end. He was tossed from being the prime villain, to becoming the "muscle" that he usually was. It sucked!
I really liked the portrayal of the Joker. He seemed more like the traditional style and mannerisms of the Joker rather than the more modern one. Given that the series is supposed to be set during Batman's early days, it's quite fitting. I did feel that he would've been better used in the final film rather than the second though since he was such an iconic figure for Batman... Although I may just be saying that because of Ledger's AWESOME job as the Joker.