I've never really felt compelled to give hip-hop more than a passing glance, but A Tribe Called Quest are one of the groups I put on if I want to see how well the genre is registering with me at the moment. Still lukewarm, at this point.
Of all the rap artists I've encountered though, their stuff is among the "safest" and least provocative and controversial, if that means anything. That's actually why I tend to turn to them though, I feel more pull from "quieter", more pop-oriented rap than gangster stuff.