Always liked this one:
Cream- Crossroads(Robert Johnson Cover)
http://www.youtube.com/watch?v=YdwVVI4B3oY
Or this one:
Blue Oyster Cult- I Ain't Got You/Maserati GT ( The Yardbirds Cover)
I saw BOC play this on the "On your Feet or on Your Knees" Tour. Damn I love the old school stuff!
http://www.youtube.com/watch?v=VgE7nD-X45Q