I'm sure all are great performances. I know (having seen him twice) that Elton John puts on a great show.
While I couldn't pick out a single performance, I want to give credit to Neil Diamond. I saw a lot of his concerts and the difference between listening to a recording and hearing him live was simply unbelievable. Of the few other groups I have seen (Billy Joel, Boston, James Taylor, Barry Manilow, the late Kenny Rogers, Judy Collins) none had as wide a distance between their live and recordings as I noticed with Neil.