I'd say the Radeon 9600-series is a better purchase than the FX5600 Ultra. The performance is about the same, but overall the 9600 seems to perform better, especially with Antialiasing.
The Tom's Hardware review seems to conclude otherwise, actually much to my surprise. They show the 9600Pro falling behind the 5600 non-Ultra in many tests. Then again, there's been many people questioning the validity of review results in Tom's these days. Thanks for the Digit Life link.
There's also a recent article (linked from AnandTech news) that said there's a bug in current DX-9 anti-aliasing hardware, and there's a workaround for ATI but not for nVidia.
Extremetech also has a series of articles about nVidia and their "optimizations". Of course, ATI is hardly innocent in this as well. Just that they didn't seem to cheat as much - oops I mean optimize as aggressively
Personally, I feel that the 9600 Pro is a more elegant design, though I can't exactly explain why when I think about it. Is it the result of a good marketing effort on ATI's part? Can't trust those Canadians, like South Park showed us
And the Sapphire Ultimate fanless heatpipe (cheaper than 9600Pro + Zalman heatpipe) is icing on the cake.
In case you're wondering, I'm still waffling over which $200 card to buy. Or should I get the DVD burner instead.
Maybe I'll just get both