I'd like to nominate Warrior on the Edge of Time, that one always gets overlooked.
Hawkwind are a hard band to pigeonhole, some call them prog, some call them rock n roll (how about prog n roll?) but that really depends on the album, they evolved a bit throughout the years. They started out as just a hard rock band more than anything, but starting with Mountain Grill they became the defining space rock band. I think one of the reasons Lemmy left was that he didn't like the prog direction they were taking.
Well that and he was a speed junkie that became such a liability for the band that they decided to just dump him in the state of Michigan somewhere.
