I don't know about the best of all time, but the best I ever saw was the night I got an unexpected jolt when my summer camp took us to see the Who and Jefferson Airplane in the summer of 1969 at Tanglewood in Massachussetts, a week before the Woodstock festival.
The jolt was the opening act . . . a gentleman named B.B. King. Five notes out of him and I was a goner. I couldn't wait to get home from camp, get my hands on the cheap little electric guitar my maternal grandma bought me for my previous birthday, and start teaching myself to play seriously.