The heaviest band I listen to would probably be Melvins, but it's a different kind of heavy. It's loaded, slow, thick, sludgey. The angry kind of kill-kill-kill heavy would probably lead me to agoraphobic nosebleed. Even though pig destroyer is the same guy only with a full band compliment, nosebleed's stuff just seems more raw and aggressive. I've listened to a lot of black metal a la Emperor, but it just doesn't evoke the same of emotion from me.
Add names to the list. I'll definately check out any bands I haven't already been exposed to.