If you could go back in time, what concert would you go to? Disqualified are Woodstock (too damn obvious) and Altamont (too damn stupid).
I'm thinking Hendrix at Isle of Wight. Or perhaps the Beatles on the Roof.
Without a doubt, Sept 1971 at the Coliseum in Houston, TX to see the Allman Brothers 3 weeks before Duane Allman was killed. Cheech & Chong opened for them. Best concert ever!