Kai Wright has an excellent piece on the forgotten radicalism of Martin Luther King, Jr. -- always a point worth making in a day and age when conservatives would like you to think they would have been standing right beside King when he marched on Washington.
That said, to some extent I think the creation of the King Myth and the displacement of the more authentic radical King is a good thing. A country doesn't get official national hero types without mythologizing and sanitizing them to a large extent, and it's a good thing, at the end of the day, that King has moved into national hero status. That said, check out King preaching on Vietnam:
That's some strong medicine.