Mostly Old school Thrash Metal (Kreator, Megadeth) some modern Extreme Metal (Like Devildriver, Mastodon), Melodic Death Metal (Like Death, Dimmu Borgir, Arch Enemy) Brutal Death Death Metal (Nile, Behemoth, Cannibal Corpse) Christian Death Metal (Mortification, Extol) and European Black Metal (Emperor, Satyricon)
Kreator and Megadeth are great, I also like... i don't know what genre it comes under, some people call it operatic metal, with bands like sonata arctica.