The cream always rises to the top but can we compare Connors, Bjorg, McEnrow, Sampras (etc.) with Federer? The game has changed so much. Courts have improved, while the evolution of the racquet is always on the move. Each during his time was exciting to watch. Each was the best during his time working within the constraints of the variables. As I said I really do not think we can compare this players from the different periods to Federer.
We cannot even compare their wins in tournaments really. Yes their are the slams that have been around forever but new tournaments have appeared on the scene and some of the players of the past have never even played in them.
I do not mean to take anything away from Roger Federer's ability to play tennis. He is the best right now and seems unbeatable except in the French tournament at Garros. Go Roger and keep up the great playing of the game.