IMO if you're upgrading you should get a better card that the GTS.....get the GTX or the 2900XT. You won't be able to run decent eye candy (my speculation) in Crysis or UT2K7, etc.
Surely that 8600GTS can run all of your current games with decent eye candy? With only a single X1950 Pro I can run all of my games maxed with 16X HQ AF, 4X quality adaptive AA and maintain 50-60FPS at 1920*1080.
Also right now baby sisting is where i get all if my income (about 200-300 a month)and i realy only have the money for the GTS,I just hope that i can get some high settings out of crysis on it and with a Phenom or INTEL quad latter on it should do a little better.