Here are the results from my request for non-shopping-oriented rap music.
Many thanks to the four poets who contributed:

Brandon Downing:

MF Doom (aka Viktor Vaughn, King Geedorah)
Zion-I
The Roots

Noah Eli Gordon:

Dead Prez
Mr. Lif
Mos Def
Jurassic 5

Michael Magee:

Mos Def
Blackstar
Cibo Matto
Common
The Roots
Outkast
Sage Francis
Aesop Rock
Mr. Lif

Rod Smith:

Scratch (Documentary)