Not a GOAT unless you've won a GS on each surface imo. Laver owns Fed
Edit: and Agassi!
Although I still think Laver is a goat contender it has to be pointed out that laver didn't win a slam on every surface. 3 of the 4 where played on grass when he won.
Only 4 men have won a slam on every surface.
Wilander. even though he didn't win Wimbledon, ao was played on grass when he won.
Conners. Conners may have not won the french but won the US when it was played on green clay.
Agassi. The modern career grand slam.
Nadal. The only man in history to hold GS titles on 3 seperate surfaces.
I change my GOAT every day, but I think if you look at Feds record of 5 Wimblys, 5 USO's, 3 AO's plus 3 FO finals that stacks up as good as anyone.
I think Rafa will be the true GOAT however. I think he has many more slams in him on all surfaces.
As for cycling. Merckx is the true GOAT. While Armstring concentated solely on winning the tour-de-France, Merckx tried to win everything every year. He succeeded for the most part too. He won 5 TDF's to Armstrongs 7 but during his prime he was knocked off his bike by a spectator and injured during another TDF where he could have made it 6. I don't think he was the same rider again.