If you had access to a time machine, what concerts would you go back to see?

@milkkefir, good choice with Joni Mitchell's 79 tour with Jaco & Metheny. Her 74 tour for "Miles of Aisles" with Tom Scott & The LA Express (Robben Ford on guitar) would also be a good choice.

@Only waytoomuchstuff, great story about the Texas International Pop Festival. I know there are bootlegs of some of those sets floating around, because a friend of mine has a copy of Santana's set. I remember the sound quality being surprisingly good for a 1969 recording; but, the only downside was their set only around 35 - 40 minutes.

I'd go back to my very first concert.  It was 1971.  Seiji Ozawa was conducting the San Francisco Symphony in an all-Stravinsky program.  They did L'Histoire du Soldat and The Rite of Spring.

Hmm, this is a good one. If I could travel back in time I would like to see the following musicians live:
Beethoven, Brahms, Bach, Handel, Mussorgsky, Mozart, Strauss, Vivaldi, Porter, Miles Davis, Coltrane, Brubeck, Bobo, Getz, Jobim, The Beatles, John Mayhall and The Blues Breakers, Yardbirds - Page, Clapton and Beck, BB King, Albert King, Zeppelin, ad infinitum. The list is nearly endless. So much great music throughout the history of man, where do you draw the line?   

1967, I was in the Navy stationed at NAS Lemoore in the Central Valley outside of Fresno California. Me and a buddy were planning on going to a concert and he had the transportation. A few hours before we were going to leave he informed me that he couldn’t go because his girlfriend insisted she spend the weekend with her. The concert was called Monterey Pop. To this day I’m still pissed!

The second concert I would go back for I actually saw.  My Navy buddy from above told me about a band he heard about that was going to be at a small club in Santa Barbara Ca..  He  said he had heard they were really good and the black guy “made the group”.  I don’t remember the name of the club but the band was called “The Jimi Hendrix Experience”.  Can you imagine hearing Foxey Lady in a small club?  What a night!