I'm part of the extreme metal nation, anything black metal, death metal, thrash metal or anything heavy and loud, I will listen to, I personally like the death metal bands Cannibal Corpse and Six Feet Under, they have a good sound. Here's a list, gives an idea. (mainly consisting of rock and metal).
Cannibal Corpse, Obituary, Morbid Angel, Death, Psycroptic, Angelcorpse, Six Feet Under, Immolation, Suffocation, Deicide, 8 Foot Sativa, Judas Priest, Pantera, AC/DC, DIO, Disturbed, Stone Sour, Lamb of God, Megadeath, Anthrax, Carcass, Children of Bodom, At the Gates, early-Metallica, early-Slipknot, Tool, System of a Down, Machine Head, Rammstein, Rob Zombie, Static-X, Severed Fifth, Metal Church, Iron Maiden, Cryptopsy, Vital Remains, Hate Eternal, Pain, White Zombie, Autopsy, Torture Killer, Black Sabbath, Accept, Motörhead, Twisted Sister, Venom, Deep Purple, Iced Earth, Sepultura, Dream Theater, Slayer, W.A.S.P, Skid Row.
Hehe, huge list. But thats not all, theres heaps more than that on me.
Sorry, but I define that as a disgrace to extreme metal.