Norwegian Black Metal
Some of the best music nobody has mentioned. Let me list some names and see if anyone responds:
Borknagar, Emperor, Dimmu-Borgir (older stuff), Nagelfar (De.), Naglfar (Swe.). There are tons of other ones, but those are probably the most well known. Sorry, but I can't forget you Finnish guys, Mustan Kuun Lapset.
Of course, Ive been listening to some lightweight stuff lately like Pain, Darude (that annoying Sandstorm song), and Jean Sibelius.