I can't choose three, but I will add the name of one golfer from the past that has not yet been mentioned, and that is Billy Casper. I had the opportunity of watching him play multiple times, and then was able to meet him in person at a clinic.
Billy was a genuinely nice guy. Happy, smiling, and kind. One of the best putters ever to play the game. He had kind of a stabbing/jabbing stroke, but the dude could seriously roll the rock. He put on a putting clinic the time I met him and it was incredible.