I have Public Enemy albums, it was politics that drove me to listen to them.
I had a work colleague who lent me the first Run DMC and Beastie Boys albums, and I listened to more of both those artists (although more of the Beastie Boys than Run DMC).
There was The Disposable Heroes of Hiphoprisy, I arrived there via Gil Scott Heron's "The Revolution Will Not be Televised" - and didn't really stretch too far beyond that.
There was KRS1 on that REM album.
But now things get a little difficult - the fear of sexism, homophobia, anti-semitism, glorification of violence, celebration of capitalism, meant that any other steps into that world were taken very tentatively, and often, not taken at all because it was easier to stick on the safer ground of indie-rock.
Low End Theory is a good, possibly great album. I've only listened to it through twice (so far) but it's musically inventive, and not harsh and aggressive like I find a lot of hip-hop - the jazz influence is clear, and the lyrics are dense and require listening, certainly more listening than I've committed to so far.
I'll certainly listen to more A Tribe Called Quest.