Cool topic! I have seen quite a few shows over the years and these three stand above the rest.

1. The Allman Brothers Band - 1992. I saw them at the Greek Theater in Los Angeles on their Shades of Two Worlds tour. This was the best concert that I have ever seen. Dickey Betts and Warren Haynes were simply awesome to see and hear and the band was arguably at their post-reunion peak. The highlight of the show was the song Blue Sky.

2. Yes - 1992. I saw this show at the Pacific Amphitheater in Costa Mesa. This was the Union tour so all the best were there including Steve Howe, Trevor Rabin and Rick Wakeman. Their verson of Heart of the Sunrise was without a doubt the single best song I've heard in concert. When the song was over even the band was jazzed as they knew they had nailed it.

3. King Crimson - 1995 (I think). I saw King Crimson at the House of Blues in Hollywood on their THRAK tour. It was a great concert and there certainly were some interesting guitar moments from Robert Fripp.

Honorable mention goes to the two Pink Floyd shows that I saw. Their comeback in 1988 had the most impact on me because I never thought I'd ever see them live. The Division Bell tour was a better show, though.