I'm the same way. It's usually some form of black metal or folk metal, with some neo-classical thrown in when the mood hits.
I like "The Extraconscious Lucidity" a lot.
As far as narrowing it down, I've been into Akhlys, Nightbringer, and Mare Cognitum lately. I really enjoy the album "The Dreaming I" by Akhlys. I also enjoy Xasthur and Nortt when in the mood for the "depressive" atmosphere.
I've been listening to Black Metal for 14+ years and I have never been able to get into Mayhem. Yeah, yeah, I've tried. Is it just one of those bands that people gravitate towards because of their history? Musically, they aren't that great, imho.