I vote Superman, because it is definitely the best Superman movie of all and gets the character 100% right. Yes, it does have problems with tone once we get to Luthor, but that first hour is just amazing. And I don't even mind the Earth-spinning. It would be troubling if there were any particularly great sequels to follow, but since all of them were more or less worse, you can pretty much look at this as a standalone film that wraps everything up nicely. And man, does this film work. The score still gives me a sense of wonder you rarely get anymore.
There were several better Batman movies, I think Batman Returns is a much better film set in the same world, and the first two Nolan films do a great job. I do admire Jack Nicholson as the Joker, but he never commits to the character enough for my taste. I see Nicholson in make-up, not the Joker. I might be spoiled by Ledger though.
So overall, team Superman on this one.