Worst: Like so many others, a drug fueled concert that had tragedy written all over it: Jaco Pastorius and Jorma Kaukonen, Lone Star, NYC, 1985. A giant mess. Jorma survived, Jaco didn't.
Some greats worth mentioning: King Sunny Ade, Roseland Ballroom, early 80's... a whole 'nutha level of musicianship than I was used to; Van Morrison early 2000's, Jones Beach, NY, I know, he has a horrible reputation, but maybe he was aware of it by now, and cared a bit more... The excellent James Hunter opened... Morrison played both classics and a bit of country and western from the Pay the Devil album, and lots off the superb The Healing Game; Richie Havens, small club in upstate NY, the man had pure music and energy coursing through his veins... I got to buy a CD directly from him; Melody Gardot, Montreal Jazz Festival, a voice as pure live as recorded; Ray Lamontagne, Radio City Hall and Capitol Theater, there are acts you see 'cause you like the band, and maybe have some fun, and there are acts you see because some just care so much to deliver a sonic experience, Melody and Ray really deliver on both.