I think his biggest match was the one versus Sampras in Wimbledon. It was sort of his breakthrough. 'Changing of the Guards' as the BBC said very poeticly...
2007 AO SF
Agree with both.
I voted for the final against Hewitt at USO.
I think the QF in USO 2004 against Agassi amd Wimbledon 2007 final are also two of his best big matches...due to what I think they represent.
Wimbledon 2004 final against Andy R was also an excellent match, which was also the real turning point in their 'rivalry' which never was.