Ok, was just going to go
at the fact Buddy Holly hasn't been mentioned when I realised that Patrice DID mention him.
Although not one of my favourites, he is undoubtedly one of the most influential musicians of all time.
Others I will mention are Ritchie Valens, Marc Bolan and Eddie Cochran
If going for the older when they died, but still died too young it's definitely John Lennon. From the list given in the poll I would choose Brian Jones coz he was the brains behind the early Stones stuff and was a musical genius. Jim Morrison would be my 2nd choice.