I'll have to say Ulver, above all, because they never fail to surprise me with each successive release, and furthermore because their compositional abilities and sense of melody are second to none.
I'd be pretty pissed if Drudkh, Xasthur, and Leviathan hung it up. And goddammit, Cannibal Corpse too. I love that band. Each release improves upon the previous, yet to me, the first few with Christ Barnes are still (mostly) relevant. I know that there are far better things that I could be masturbating over, but I've always been a fan of that band, and Kill is an incredible death metal record, as full of hatred and spite and bile as anything any other band has done.