I'm thinking it must have been by BB King, since all the time you're hearing people say they'd rather hear one note by BB King than "n" notes by "x" number of other guitarists. But not to leave anyone out, maybe there should be two categories. a) best note played by BB King. I mean he must have had some days that were better than others. b) best note not played by BB King, which is understood to be worse than all notes played by BB King. Of course I don't mean "notes which BB King chose not to play". I really mean "notes that people who are not BB King did choose to play".