I'm a huge metal-head. I love pretty much all genres of metal: Power, Thrash, Speed, Death, Black, Grind, etc.
Some of my favorites:
Thrash:
Metallica
Megadeth
Trivium
Slayer
Mercyful Fate/King Diamond
Death:
Nile
Cannibal Corpse
Morbid Angel
Hate Eternal
Cattle Decapitation
Black:
Sargeist
Darkthrone
Emperor
Venom