I'm into everything: classical, folk, opera, world, prog (Genesis, Gabriel - part of the reason this course drew my attention, Porcupine Tree, etc), heavy metal & death metal, but metal is the core of my listening.
Sabbath and Rainbow got me started, then on to Maiden and Metallica, Pearl Jam and Soundgarden, and now I'm heavily into the likes of Meshuggah, Insomnium, Gojira, Opeth, etc. Always looking for new music I've not heard before.