IMO this year's US Open final was Federer's worst GS final,
maybe even worse than FO 08, because Nadal was just godlike that day.
At USO 09 Fed choked big time in the second set and again in the fourth,
he should have finished the job after Delpo's DF collapse. Fed's serving was atrocious throughout the match.
AO 09 actually was a great match IMO, except the fifth set. Fed was really good off the ground, but his serving was below average. He should have made the difference at the end of the third set, when he blew several BP's by playing too passively.
Wimbledon 08 wasn't a bad match by Fed, Nadal was just better. Fed almost came back from the dead, but in the end the better man won. OK, it wasn't the best match Federer ever played, but by no means as crappy as the USO final.
Just my opinion though...