I like Immortal Technique. Tupac was also a pretty good rapper in that department.
The socially aware rappers and I know they're out there, are usually with independent labels and sorts like that so to obtain their stuff and to hear it may be harder then let's say, Chipmunk's stuff. All those big record companies don't want their starts focusing on what's REALLY going on. But they're out there... they are but you have to find them.