I never got into the really hard stuff just alternative rock, grunge, nu metal, alternative metal, and a little industrial: Deftones, System of a Down, Disturbed, Linkin Park, Pearl Jam, Rage Against the Machine, Korn, Mudvayne, Foo Fighters, Red Hot Chili Peppers, Nine Inch Nails, Godsmack, Audioslave, Orgy, Tool, Static X, Three Days Grace, Cold, White Zombie and Rob Zombie, and a little Marilyn Manson, Slipknot, Chevelle, Alice in Chains, and Rammstein. Yeah, I was into all of the mainstream stuff. The darkest song I have on my mp3 player is "Digging Up the Corpses" by DevilDriver. The hardest song would have to be "Death Blooms" by Mudvayne.
This is the only female act on my rock playlist.