I'll copy the list of bands I saw at a festival 2 weeks ago:
Day 1:
Sevendust
Drowning Pool
Killswitch Engage)
Puddle of Mudd
Skillet
Papa Roach
Deftones
Rise Against
Nonpoint
Three Days Grace
Godsmack
Day 2:
Apocalyptica
Five Finger Death Punch
Bullet for my Valentine(Front row. Absolutely amazing)
Amberlin(Only part)
Coheed and Cambria(Fromt row. Got amazing pictures)
Theory of a Deadman
Slash(Yes, the guy from GnR)
Seether
Rob Zombie
Limp Bizkit
Full lineup from that show:
http://rockontherange.com/lineup.html
Went to a festival called X-Fest last year. It's a smaller show. Last years lineup:
Alice in Chains, Mudvayne, Our Lady Peace, Hollywood Undead, Cage the Elephant, Hurt, Red, Cavo, Sick Puppies, and Halestorm, plus local bands Three Barrel, Chapter of Progress, Shamus Stone, and Hollows End.
I'll be going again this year, but I have no idea who's playing.