I'd make seperate forums for each band (since fans of one might not be fans of another) -- with a 'general' forum seperate to all of them for people to mingle outside of the specific band forums. This has worked well for me.
For example (based on my forums), fans of Opeth are not necessarily fans of Area 54, but they talk music in the general forum and become friends, when they might not if they shared just one forum and ignored posts about bands they didn't like.
If this makes sense!

LOL
(btw, by 'forums' I'm assuming you mean forums within a main discussion board, like mine...?)