Couple of random ones off the top of my head. I'll agree with
The Mars Volta's debut, too.
Descendents -
Hallraker Live!
A friend found this tape in the school parking lot in the early 90s, and we fell in love instantly. It got me into punk.
Skinny Puppy -
Last Rights
My introduction to the band. I hallucinated while laying on my bed in the dark, prior to ever having done an drugs. The start of an obsession.
Modest Mouse -
The Lonesome Crowded West
I'd heard
The Moon & Antarctica before this and liked it, but this one was just woahwtfawesomeman!