Godspeed! You Black Emperor!
definitely. Check them out.
Bob Dylan, obviously.
Radiohead, for sure.
Public Enemy, back in the day.
Beastie Boys, though not so much in their music.
Manic Street Preachers, though they can be a bit strident(to put it nicely) at times.
But the Emporess of Political music has got to be the divine mme. Spears.