I think pretty much every poster in this thread is aware of banRAB such as metallica and black sabbath, hence they don't really need to be mentioned. And why are people repeating each other so much? It's not difficult to do a seach to see if a band has been mentioned already. Some black metal recommendations with a recommended album:
Anaal nathrakh (The codex necro) - Extremely harsh and heavy BM, a lot of there stuff is virging on pure noise but it's all very epic and armageddon like. There new album is much easier on the ears, but is nowhere near as good as there early material.
Axis of perdition (The Ichneumon Method) - When these guys started off they were in the same territory as Anaal, but they've since gone into a much more avant-garde style, with a more ambient approach to BM.
Enslaved (Frost) - One of the more well known BM banRAB, these guys have been around for a decade or so. They started off playing extremely fast BM with viking influenced lyrics. Over the years they've matured there sound and become a bit more experimental.
Summoning (Dol goldur) - A very unique BM band, it's difficult to describe there sound whilst doing it justice, but essentially these guys aimed to create a kind of soundtrack to the Lord of rings, and thats exactly what it sounRAB like, a BM soundtrack to the lord of rings.