Re: 8800gts ~ $80
Nice price for the GTS and yes you will notice the improvement.
I've had to drop back to my 8800GTS 640MB as my 9800GTX started artifacting something terrible, dodgy NVIDIA G92 core imo, it's on its way to Asus RMA, the good old reliable GTS just stepped up to the plate with no problems, in fact I think it does as good a job tbh.
If you haven't already bought it I'd say go fo gold, drumthrasher does have a good point also.
E8600@ 4.25GHz, 1.325V | Thermalright Ultra 120 eXtreme + Scythe Slipstream 120 | Asus Rampage Extreme| 4GB Corsair 2000MHz 8-8-8-24 @ 1600 6-7-6-24| ASUS 9800GTX| Pioneer 18X SATA DVD-RW | 320GB + 500GB WD SATAII | Antec True Power Trio 650W | Thermaltake Sonata | Vista Ultimate x64 SP2/Win7 Ultimate