Not all rap/hip-hop music is full of lyrics detailing drug use, violence against women, and more f-bombs than a George Carlin HBO special. Common, Beastie Boys, The Roots, and a lot of 80s rap artists/groups are the antithesis of the gangsta rap genre. You can't judge the whole by some of the parts.
I think the only two MCs that don't fit in what I described, yet I still really enjoy, are Jay-Z and Nas. I don't always agree with their lyrics, but I can't deny they're supremely talented.