Last year I saw a screening of Until the Light Takes Us, a documentary on black metal and perceptions of the genre/scene by its key figures, featuring most prominently Darkthrone's Fenriz and Burzum's Varg Vikernes.
I really enjoyed it. Not so much for its analysis of the genre (which has been exhaustive in recent years) but for 3 reasons: 1) banal, slice of life coverage of Fenriz, one of metal's great tastemakers, 2) rants of the sociopathically charismatic Vikernes and 3) some great cringe-inducing scenes dealing with the co-opting of BM culture.
Although black metal movies aren't too popular amongst the dedicated, this documentary is pretty respectful and entertaining.
Posted by the filmmakers at the following website: http://www.blackmetalmovie.com/moviepage.html