Some of my fav's (just looking down iTunes A-Z here):
AFI, All Else Failed, All Out War, American Nightmare, Amon Amarth, Anthrax, At the Gates, The Beatles, Big Business, Big L, Black Sabbath, Blacklisted, Botch, Danzig, Darkest Hour, Decapitated, Disfear, Doomriders, The Doors, Down, E. Town Concrete, Electric Wizard, Evergrey, Every Time I Die, God Forbid, Hatebreed, The Haunted, The Hope Conspiracy, Hot Water Music, In Flames, Insomnium, Integrity, Isis, Jena Berlin, Jimmy Eat World, Jimmy Hendrix, The Killers, Lamb of God, Led Zeppelin, A Life Once Lost, Lifetime, Machine Head, Madball, Mastodon, Meshuggah, Metallica, Minus the Bear, The Misfits, Nas, Nightrage, The Notorious BIG, Oasis, One Dead Three Wounded, Pantera, Pink Floyd, The Rolling Stones, Saves the Day, Saviours, Sepultura, Snapcase, Soundgarden, Stone Temple Pilots, The Sword, Terror, Testament, Tom Petty, Torche, Turmoil, The Wu-Tang Clan