Mage farming music: heavy metal, emo, screamo (System of a Down, In Flames, Escape The Fate, and Atreyu, my chemichal romance)
Warrior: classical, emo, screamo, throw in some drowning pool, and rammstein <---lol, they pwn (motzart, bethoven, and other classical artist, and the emo and screamo of course is atreyu, in flames, and escape the fate)
rogue: rock, and rammstein (foo fighters, velvet revolver, guns 'n roses, and other...rock bands, lol)
shaman: prodigy is the only band that comes to mind, cant really find any kind of music for that unique class.
paladin: rarely choose rammstein for this class, emo and screamo(as the ones listed for mage)
druid: alot of dragonforce, just maybe a few emo songs and blast dragonforce
hunter: screamo, mostly in flames, metallica, and some really old rap (LL cool j, sugar hill gang, and beasty boys)
warlock: grunge and rock like band's (nirvana, crossfade, maybe a few dragonforce songs, and a little in flames, also use some hubastank)
priest: classic and screamo, perfect combination for some odd reason
i think that is all classes, all you have to do is search these band names up on limewire and find some of their songs that you like, i hope you find this post useful