Crass - Best Before... 1984
Contrary to what the name would lead you to believe, this is not a greatest hits compilation. This was a posthumously released collection of various Crass singles together with a booklet which has an extensive essay on the band's history. That's probably the best reason for owning this record because half of the songs are terrible. Seriously. They should have broken up in 1981 because the music gets progressively worse track by track. (Listen to Smash The Mac and try to convince yourself that it's the same band responsible for the Feeding of the 5000.)
That said, the first nine are real fucking anarcho-punk gems that to my knowledge weren't released on studio albums with the exception of the first track.