As you state in your last paragraph…”in your opinion..” Everyone is going to have a different set of parameters for what would qualify someone as “the greatest vocalist of all time.” I do remember the first time I heard “Careless Whisper” back in ‘84, and thinking “this guy can sing!” George Michael certainly was one of the best singers of his time. I’m in my 60’s, and have loved listening to music since I was a little kid. In my humble opinion, the top two vocalists of all time (based randomly on purity of tone, range and the ability to reach me emotionally) are Ella Fitzgerald and Annie Haslam of Renaissance.