Well it is a tough choice but here are some of my favs that changed my life one way or another...
1. Jimi Hendrix at Atlanta Pop Festival July 4, 1971 (with Mitch Mitchell & Billy Cox)- Star Spangled Banner on acid. Bombs, rockets, etc. WOW!
2. The Who, The Tommy Tour 1969 at Filmore East, NYC - A few months after they recorded "Live at Leeds" when "The Who" were "The Who" not whatever they've become. So much for "the revolution"! Won't get fooled again! Ha!
3. Led Zep summer 1969, indoor/outdoor venue near where Shea Stadium is today. VERY LOUD. Young and hungry. English electric blues supreme.
4. "Woodstock" August 14-16, 1969; various artists. Big party on and off stage.
5. The Clash, London Calling Tour, 1979, The Warfield, San Francisco. Rock and Roll is alive and well after years of playing second fiddle to 70s Soul and funk music; Marvin Gaye, Earth Wind and Fire, etc. etc. White light, energy pulsing from the stage.
And many, many other shows...Small Faces with Rod Stewart (the man with the most talent who threw it all away for Hollywood $$$, Traffic (Steve Winwood)- John Barleycorn Tour.