Federer has ALREADY surpassed Sampras
Talent and greatness in sports are not unrelated but neither are they one and the same. Greatness denotes accomplishment. In my view Michael Jordan was not the most talented basketball player ever, but undoubtedly the greatest. Similarly, Sampras had less all-around ability than Agassi, MacEnroe, and, well, even Martina Hingis, but in terms of greatness, he exceeds them and all but a few players in history. Empirically, I find it hard to accept that anyone honestly doesn't see that Roger is easily more talented than Pete and everyone else in the last thirty-five years (I never saw Laver play). But, to the point, talent aside, I would argue that Fed's resume already is ahead of Sampras'.
Sampras never won more than two Slams in a single year. Federer has already won three in one year and done it three times. The closest Sampras came to the career Slam was a single semifinal appearance where his conqueror was Yevgeny Kafelnikov, who I don't think anybody would qualify as a tennis great. Federer, on the other hand has two finals appearances and a semifinal to his credit, and the man who stopped him from winning those three French Opens is probably the best clay-courter ever. I love Agassi to death and cherish the fact that he won every major, but he wouldn't have been able to sniff that feat if he played in the era of Rafael Nadal.
Additionally, when determining the best player of all time, shouldn't that player be the best overall player, taking every surface into account? If we were to compare where Roger and Pete rank on the three primary surfaces in tennis during their respective careers it would look something like this:
Federer: grass-- 1st/ hardcourt-- 1st/ clay: 2nd
Sampras: grass-- 1st/ hardcourt-- 1st or 2nd (either Agassi or he)/ clay-- 99999999e
You know that number that appears on your calculator when the total gets too high? I mean you could pull a random janitor off the streets of Barcelona, and he could beat Pete on red dirt....
There are other ways to look at this too. Pete's 14 Slams spanned the 13 years between 1990 and 2002. Roger's 12 have come in the five years between 2003 and 2007. Pete retired at 31 with 64 total titles. At 26, Roger has 51. Roger has made it to ten straight GS finals. Pete never could make more than three straight. And the list goes on....
The major detraction that people hurl at Federer is that he plays in an era of less competition. Gee, I wonder if that's because he keeps winning everything? How many more Slams would Nadal, Hewitt, Safin, and especially Roddick have if Roger wasn't around? Or another way to put this is that I guess Pete wasn't good enough to keep the players of his day from winning more majors.