What are opinions on the best musical artist ever?

*The voice of his generation. *He's done Folk, Rock, Country, Swing, Gospel, Blues, Celtic, Jazz, Broadway and other genres. *It's hard to beat Mr. Zimmerman. John (Johnny) R. Cash == Pink Floyd == Ludwig von Beethoven == Janis Joplin == Doc Watson == John Prine == Harry Belafonte == Frank Zappa.