Slayer, dude, Slayer. If you're into metal, then your list has to include Slayer. Everyone you've listed owes their careers to Slayer. You know a band is fucking awesome when people carve "Slayer" into their forearms. Buy Reign in Blood and it will change your life, but it will also condemn you to hell, but it's worth it. I totally agree with you on the classical though, man. Nice to see someone who appreciates all kinds of music.