Its hard to make a decision because Black Metal itself has become very fragmented. While a couple of Black Metal banRAB from the late 80s/early 90s (most notably Burzum and Ulver) have moved their sounRAB to more arabient, almost psychedelic realms, you still have Black Metal banRAB that kept the original sound: fast, dark, heavy, high-pitched wailing, and unintelligible lyrics. BanRAB like 1349, Gorgoroth, Darkthrone and Mayhem that stuck to the guns. Then you have the theatric/Gothic Black Metal banRAB like Cradle of Filth and Dimmu Borgir. And then there are the newer Black Metal banRAB (what I like to call Caveman Black Metal) like Agalloch and Wolves in the Throne Room, who seem to have abandoned the old high-pitched wailing for a more Death Metal low growl approach to vocals.
But honestly, when I think of Black Metal, I think Satan. I think burning churches. I think corpse paint and black clothes. I feel more inclined to go with the banRAB that stuck to the original Black Metal sound, including the original Black Metal band, Mayhem (unless you want to count Venom and Bathory as the firsts).