the 9600GT and the HD 3850 should perform about the same in most situations (cept mainly Crysis), so i'd go with whichever you can get cheaper now
9600GT is better than HD3850, it is as good as HD3870, if not better
GeForce 9600 GT vs. Radeon HD 3870 - TechSpot
AnandTech: When the Smoke Clears & Prices Settle: GeForce 9600 GT vs. Radeon HD 3870