The 9600GT SSC will rape that 8800GS. the 9600GT is a re-branded 8800GT just 5% slower.
Go for the 9600GT regular edition and save some bucks, no need for SC or SSC editions.
It would be better to get the 8800GTS 512Mbs though as it will save you money and its faster. Its basically an improved 8800GT.
No offense, but you're full of it. 9600gt's g94 core with 64 stream processors is exactly half of 8800gts's g92 core with 128 stream processors, and a little more than half of 8800gt's g92 core with 112 processors (16 disabled). It does run at higher stock clock, but this also limits overclocking headroom, and gap in performance is big. How is it a rebranded 8800gt? They run on completely different gpus (g92-g94).