It really depends on what you like better.
Band is awesome. You get a lot of creative freedom, and if you like listening to music and playing it, you'll like band. Also sometimes they let you write your own stuff.
Art is also really cool. There are different kind of art electives sometimes, so if you're not good at drawing you could take 3-D art. Or if it's just a general art class, you get to do a lot of cool things.
Personally I'd pick band, but that's just because I suck at artistic stuff. Again it depends on you and your intrests.
