Here are two Youtube links to some very nice footage of legendary guitarist Clarence White performing a few bluegrass classics with two different groups:

I am a Pilgrim / Soldiers Joy (with brother Roland White on Bob Baxter’s “Guitar Workshop” in 1973): 

 http://www.youtube.com/watch?v=CMQuuZNvwLU

New Camptown Races / Dark Hollow (with Bill Keith, David Grisman, and Peter Rowan, aka MULESKINNER):

http://www.youtube.com/watch?v=0RkxpFvo__k