I know iv put this in the TV and Film section, but i mean the characters from the comics not the camp and slightly limp wristed characters from the Movies and TV shows, (Batman Begins Excluded).
As Superman actually has superpowers by virtue of being born on Krypton and is known to be virtually indestructible you'd have to say the odds would be on Supes. Batman's just a regular guy who's certainly handy in a pub car park brawl, but he's bolstered by hi-tech gadgets and not inherently super powerful. Surely his only chance would be to use some of Bruce Wayne's money to purchase some Kryptonite and do it that way. Hope this helps.
Superman would win,but if Batman got hold of some Krypton it would be a different out come, But I hope superman cos batmans a ******** and I fancy Lois lane like mad ( Terrie Hatcher)