Goatlord is hands-down my favorite Darkthrone release, simply because it is merely an old practice tape they later overdubbed with some bizarre non-sequitur vocals. The result is discomforting and intimate. Musically, this is some of Darkthrone's most interesting material. Before the icy blur of Transylvanian Hunger, Darkthrone were a bit more experimental and some of the work here sounds almost like the angular, instrumental math rock that was popular a few years later in the states. Many dismiss this as mere filler in the otherwise stellar Darkthrone discography, but to them I say, eat a bag of dicks. This is the most kult release by the most kult band. That alone should be enough for you.
Oh, and check out the Rorschach test Fenriz did for my other blog.