First concert was around 1972; "Peter Green-era" Fleetwood Mac at the Brooklyn Academy of Music...in Brooklyn, NY

. I was pretty young and not really up on the Blues scene at the time, so I wish I could go back in time to see it again.
Other notables...(don't hold me to the dates)
Moody Blues at Madison Sq Garden, circa 1973
Allman Bro's, The Band & The Dead at Watkins Glen;
Lynyrd Skynyrd opening for Joe Walsh in Mobile AL, circa 1974
Gang of Four at NYC's Roseland Ballroom, circa 1981-ish;
The Clash at NYC's Bonds International Casino (opening night) 1981;
Pink Floyd The Wall at Nassau Coliseum;
U2 War tour at the Orpheum, Boston;
Peter Gabriel at the Palladium, Worcester, MA
That's all for now...brain hurts...