Anybody mentioned Until The Light Takes us? Its pretty much the Exorcist of documentaries, is there such a thing as a horror doc?
I, too, thought it was pretty fantastic. Not being terribly familiar with black metal, I wish they would have included more of the actual music from that scene in the documentary. But that was my only complaint.
Oh and a warning that they were going to show a picture of the album cover showing the lead singer's head blown off by a shotgun.