After you buy your new video card, post back on how everything goes and how you like it.
I myself would upgrade to a GF4 Ti series card, but my GF3 is doing fine now and I think I want to wait till the NV30, or maybe the new Radeon but not sure. I have only had Nvidia cards since the TNT series (TNT, GF2 GTS, GF3Ti200) and they have all worked great. I still have them all too
So I'm reluctant to try the Radeon but if the price is right who knows.