Surprisingly touching, moving and enchanting, this one may be my favorite of the three. I don't know that the 3D is absolutely necessary - it's not bad but I think the movie stands on its own without it.
I have been a Batman fan since I was a little kid and this is by far the best of the entire series. Heath Ledger was so mindblowingly amazing I went back and saw it again the next day after seeing the midnight showing on opening. Really fantastic.