What monitor do you use? If you have a 21" inch or plan to upgrade, i would recommend the 8500. I havent seen any tests between a GF4 and the 8500 when it comes to 2D-quality, but some articles points out that the GF4 has a better 2D quality than earlier GF-cards. For hi-res monitors I would not recommend the GF3, except Leadtech's card which apparently has better filtering.
Trust me, a fuzzy 2D image in hi resolutions is reeeaaaly annoying. I used a Matrox G400 before, and my current Kryo II can't quite live up to its lush and sharp image. Used to have a perfect 1800x1400 res before, had to drop down 1600x1200 with the kryo, and its somewhat blurry at the edges. But it's far better than the GF2 i tried before getting the kryo.
IMO you should get a card that fits your monitor and not be blinded by miniscule diffrences in FPS.