OK I realize I'm setting the standard for being the oldest fucker on the board.
First - Elvis Presley at MLG 1st concert in Canada 1955, before the movies and all the other BS. My boss got floor seats and gave them to me.
Best - A tie: Ray Charles at Massey Hall 1959 on tour, backup acts included The Drifters, The Olympics, Ron Holden but Ray was on the top of his game.
Mavis Staples at the Toronto Jazz Festival summer 2007, she turned a grey haired Toronto audience into a rockin' southern baptist gospel congregation, hairs goin' up on the back of your neck, booty shakin', emotional performance.
Worst - Rolling Stones at the SkyDome early '90s, absolutely terrible. Nothing redeeming about it.