No doubt that the best shows I saw were the Frank Zappa concerts I attended:
Cologne 1979, 1980 (together with Santana), 1982, 1988
Frankfurt 1992 (The Yellow Shark)
Besides some Dylan shows incl. his recent appearance in Düsseldorf. Tom Petty 1992 in Essen was pretty cool as well.
Heres a few that come to mind:
Phish opened for Santana in 92 in Tucson,AZ
Trey and Carlos playing together was a real treat!
1997 MMW at the High Sierra Music Festival
Santana in TJ Mexico in 92... in a bull fighting ring no less...
All ZERO shows in the bay area I attended!