For all those who write that Agassi got lucky...he got just as lucky as Sampras did that Philippousis wrenched his knee at Wimbledon ... he got just as lucky as Federer getting 5 days off during Wimbledon while Nadal had to play every day ... he got just as lucky as Lendl when McEnroe choked at the French Open when Mac was up 2 sets to love and up a break in the 3rd ... he got just as lucky as Chang who served underhand and won a point against Lendl ... he got just as lucky as Nadal who got to play Djokovic and Gonzales after they had long 3 set matches and wore each other out before playing him...
Guess what...ALL THE GOOD PLAYERS GET LUCKY!!!
Winning all 4 Grand Slams on 4 different surfaces = the greatest player ever.
I'd agree that winning a career Slam is a very impressive acheivement, and I don't buy the "luck" argument either. Every top level "great" player who has won a lot of Slams has had luck at one stage or another. So, I wouldn't take anything away from Agassi just because he beat Goran and Medvedev in the finals of Slams.
That said, I don't know if his career Slam accomplishment catapults him to best player ever. Clearly you've picked your criteria - Career slam, multiple surfaces, and made your pick. I don't agree with it, but at least you explain, in plain terms, why you made it.
As far as "4 different surfaces," as I've said many times on TW, I tend to see Rebound Ace as simply a variant of a hardcourt, which it is. I realize it plays differently than the USO, but the true bounce, true footing nature of a hardcourt is still it's main characteristic. Kooyong grass played differently than Wimbledon grass, yet we're not ready to say Wilander won Slams on 4 different surfaces (Kooyong grass, Clay, USO Open hardcourts, Rebound Ace).
But, I guess that's a side argument. Rebound Ace and the USO hardcourt aren't exactly the same, so I can't deny that they are not different surfaces if we define surfaces narrowly. I simply think winning Slams on those two particular surfaces - Rebound Ace and Deco Turf at the USO -- isn't that remarkable of an accomplishment, because IMO opinion, they are both simply hardcourts.
Just off the top of my head - Lendl, Wilander, Edberg, Sampras, Safin, and Becker all won on AO Rebound Ace and on USO Deco Turf, which suggests that there is no great adjustment or variable skills necessary to be successful on both.
Of course, none of this changes the fact that Agassi won the career Slam.