I'm more a hardcore/punk and metalcore addict myself, but I'll try answering your questions...
Let me just say one thing Slayer are the kings of all metal!!!
Heavy Metal - Slayer
Black Metal - Celtic Frost
Death Metal - Terroriser
Gothic Metal - Paradise Lost
Symphonic Metal - Dream Theather
Power Metal - The Haunted
Nu Metal - System of a Down
Industrial Metal - Prong
Speed Metal - Sodom
Or something like that...
