Do I even have to post my favorite? Well maybe I will for the n00bs.
AC/DC
Daylight...
Led Zeppelin, Junoon, Pink Floyd
more daylight...
Pantera, older System of a Down, older Rage Against The Machine, Vital Signs (mostly for their last album together), some Metallica, and love a bit of the Doors, Hendrix, Black Sabbath, Guns 'n Roses, Alice Cooper, Nirvana, Lou Reed, Johnny Cash, Queen, Jet, Fuzon, Korn and Amy Winehouse.
Have been really liking Pearl Jam and Radiohead lately along with the more obscure bands like Ruiner and Parlor Mob, and of course my friend's band Mourning Son.