I agree totally. Federer, more than anyone in the past 6 or so years, has been closest to Sampras in the clutchness you mention - an ability to produce serving magic when he's break point down or 0-40. Roddick, Ivo etc pail in comparison in this area imo.
On Roddicks serve and accuracy. While great, I think it is too often quite predictable. Sure he can throw down bombs but, as we've seen from many players with 220km/h serves, it doesn't really pay off that well if you're serving them within reach of the returner (Fed on many occasions has made Roddick's serve look easy to return). On the other hand Sampras and Federer could/can serve 20km/h slower but within an inch of the corners and get way more benefit from their serve. "Dime serving" as Agassi calls it - the hardest serves to defend against and which only a couple of players at any time can pull out at key moments as those two.
An example of this can be seen in Federer's loss to Berdych at Wimbledon. Tons said Berdych was slamming down big serves but Federer actually hit more aces, fewer double-faults, had a higher winning % on his own 2nd serves, and a faster 2nd serve average speed. (he just let himself down elsewhere and Berdych was on fire when it really mattered)
