Eragon
Banned
In my opinion, Nadal has (just) surpassed Borg.
They're certainly in the same tier of greatness, though. You can't put Borg a tier above Nadal.
I don't like using tiers but if I had to use them.
Tier 1: Federer
Tier 2: Sampras, Nadal, Borg
Tier 3: Rosewall, Laver, Agassi, Lendl, Connors, Gonzales, McEnroe
I'm certain Djokovic will get to tier 3, at least.