I don't know if Frank Zappa fits your criteria, but he was a singer/songwriter/composer/satirist/multi instrumentalist who could fucking shred on the guitar.
He also had the greatest quote ever in regards to the "Does music make you worship satan and kill people?" debate: "I wrote a song about dental floss, but did anyone's teeth get cleaner?"
Mark Linkous and Elliott Smith kicked ass
Amy Winehouse was horrible. Mediocre voice and her serious and mental problems was too much for me. Can't believe that people genuinely worshiped her. Shows how sick some musicians were/are.
Jim was good WITH the doorsJim Morrison is vastly overrated
All of those had long and varied careers whose legacies where already cemented before they died.Frank Sinatra
Ella Fitzgerald
Dean Martin
Johnny Cash
Kinks