Becker - Very first match I ever watched was Becker-Curran 1985 Wimbledon Final. Made me a tennis fan. Back in those days, I was a kid who loved big strong guys...favorite superheroes were all big strong guys. My one superpower would've been super strength, all that stuff. Becker matched all that and more. Big guy, big huge serve, powerful forehand, all that stuff. Plus he had enough flair in his matches to make it fun. His rivalry with Lendl was fun too.
McEnroe - Never have I seen more of an "angles" genius in my life. For all of his faults, the guy just knew how to hit shots, time and time again, that were impossible for the very best in the world to hit. Even when he was fading away and not winning regularly anymore, you'd see him hit those angles against Courier, or someone of that nature, and Courier knowing he had zero chance at it...and those guys at that level get just about everything. Not to mention that JMac had a court sense like Larry Bird had basketball sense.
Connors - Simply loved the fight he exhibited every single match. He'd hustle against the 500th player in the world...hated even conceding a point. Love that attitude.
Edberg - Net game was Picasso-like, and I always loved his second serves. Nothing like Federer, but he had a dancer's like footwork too. Beautiful to watch.
Sampras - Simply...the serve. Wish he would've adapted on clay, but his dominance on grass is only matched by one man.
Ferrer - Goes without saying, and everyone here knew this would be coming. Just love his consistency every single match. Even when he's getting beat to death(like the RG semi against Nadal), he keeps fighting, grinding, and hitting. Places the ball beautifully just about every single shot, and outside the Top 3(Murray can't do this), it's near impossible to force him into multiple mistakes, so breaking him is a rare gem. His constant winning is not a fluke. No big weapons, but his whole game is one big weapon.
Nadal - Idiot fanboys aside, this is one of the all time greats. So much fight, and he has an uncanny ability to come up with an unreal and impossible shot to change the course of a match more than anyone I've ever seen.
Federer - Simply the Maestro. The James Bond of tennis, with the unmatched combination of strength and grace. Never seems to sweat, and never makes a noise on the court(footwork I mean). The greatest of all time, and I hope to see him play in person before he retires.