sampras - agassi was a lot like federer-nadal in terms of excitement.
But federer-nadal takes it up one more level on pete-andre in terms of drama and history.
Djokovic - nadal is an awesome rivalry purely because both guys can take matches from each other on all the surfaces.
It is a very even rivalry. I think djokovic - nadal can be even greater than agassi-sampras historically provided nadal can get back to the top.