Any good bands?

i need some more music for my ipod. my favorite genre is rock/alternative and some types of metal. here's a sample of what i listen to: korn, three days grace, breaking benjamin, ozzy osbourne, ac/dc, aerosmith, disturbed, atreyu, bullet for my valentine, and so on. i know, i basically listen to mainstream, but do you know of any good bands who aren't that popular but are still good? thanks in advance.