I would say John Lennon or Hendrix. I don't really think there is an explanation needed for that, seeing how they are still VERY influential today. I think if they were both still alive, they'd still be making some kind of music.

I'm suggesting that Stevie Ray Vaughan be put on that list as well. He's one of the greatest guitar players ever, and if he were still around today I think he'd still be making some kick ass music and guitar riffs. You want pure rock and roll, listen to him and Double Trouble. Just my .02 though.

Kurt Cobain was overrated, as was Nirvana. I still like some of their music, but I don't think he would be talked about near as much today if he weren't dead. I think he would have faded out.. Pearl Jam is much better, IMO.