I'm going for most eclectic.
Jefferson Airplane--Grant Park, 1969
The Band--numerous times, the first at the Aire Crown theater, 1971
Woody Allen (with, believe it or not, Jim Croce opening)--Mill Run Playhouse, 1972
Mahavishnu Orchestra--Aragon Ballroom, 1973 (my most jaw-dropping concert)
Steve Martin--Amazingrace, circa 1974 (He knew he was funny and he was going to kill you.)
Bruce Springsteen--Auditorium Theater, 1975 (better than expected, but never had interest to see again.)
Gary Burton with Pat Metheny and Mick Goodrick--Amazingrace, 1975
Keith Jarrett--Amazing Grace--1975
Pat Metheny's first group--Amazingrace-1976
Spinal Tap--Club Metro--circa 1986
Fishbone--Club Metro--circa 1986
Ron Carter with a string quartet (!)--Catalina Bar & Grill, 1999
Charlie Haden and Quartet West, Wadsworth Theater, 2004
Cream reunion--Madison Square Garden, 2005
Additional shows, Charles Mingus, Carla Bley, McCoy Tyner, Bill Cosby (pre-Quaaludes, 1969), George Carlin (in Vegas), Art Blakey and the Jazz Messengers, Cecil Taylor (the most difficult concert I've been to), Ted Nugent and the Amboy Dukes opening for Tiny Tim (!) and Frankie Valli and the Four Seasons (I the only hippie in a sea of greasers and girls with giant blonde bouffants).