My hip-hop knowledge is about 6 years out-of-date, but...
Quasimoto,
The Unseen is a super whacked-out and stony record with great jazz samples.
Group Home is awesome--they were Gang Starr proteges (I think they guest on
Hard to Earn) that never really went anywhere:
http://www.youtube.com/watch?v=TI264qcI2loI mentioned the Slaughterhouse LP, but the single is a winner for cover art:

I saw Slick Rick with Doug E. Fresh and the Biz right when he got out of jail. Dude got fat and the promoter must have lost a mountain of money--I think there were a couple hundred people at The Paramount (which is a 2300 capacity venue).
The Great Adventures of is obviously a classic, but
The Art of Storytelling is pretty great too. I can't get myself to ride the skateboard.

Lastly, Seattle needs some sort of representation in this thread.
