Not sure where they rank on a list and this definitely isn't complete, but just the first several albums that pop to my mind as ones I listed to a ton at various points in the 90s. Before judging me, remember that the 90s covered me from kindergarten through 9th grade.
Weezer - Weezer (Blue)
Weezer - Pinkerton
Nirvana - Unplugged
Pearl Jam - Ten
Counting Crows - August and Everything After
Sublime - Sublime
Barenaked Ladies - Stunt
Live - Throwing Copper
Hootie & The Blowfish - Cracked Rear View
Fugees - The Score
Greenday - Dookie
Offspring - Smash
Collective Soul - Collective Soul
Foo Fighters - Foo Fighters
Alanis Morisette - Jagged Little Pill
TLC - Crazy Sexy Cool
Dave Matthews Band - Under the Table and Dreaming
Presidents of the United States of America - Pesidents of the United States of America
Smashing Pumpkins - Siamese Dream
Aladdin - Soundtrack
Lion King - Soundtrack
Solid list. If I made a mashup of this and Sean's list it would probably be about perfect for me. I may have some Stabbing Westward in there, some more early hip hop, some Blink 182...but then again I'm all over the place.