I'd like to call myself a metal head, even though I know a lot of people that listens to stuff that is way more hardcore than what I prefer. However, I think I've spread to a lot of different genres:
Heavy Metal; Black Sabbath, Dio, Rainbow
Thrash Metal; Metallica, Slayer, Megadeth mainly. I've heard a few songs by Testament that I really like.
NWOBHM; Judas Priest, Iron Maiden.
Nu Metal; Slipknot, System of a Down, Disturbed (not so much anymore, though)
Progressive Metal; Dream Theater (some of it), Liquid Tension Experiment, Gojira (some of it)
Symphonic Power Metal; Nightwish, Rhapsody of Fire
Stoner Metal; The Sword, Kyuss
Avant-Garde Metal; UneXpecT, Diablo Swing Orchestra
Heavy Rock; Scorpions, Queens of the Stone Age, Alice In Chains
Progressive Rock; Muse, Queen, Rush (some of it)
Alternative Rock; Rage Against The Machine, Red Hot Chili Peppers
Metallica, System of a Down, Nightwish and UneXpect have a special place in my heart, though.