I second the 7600, great graphics card, i have the GO Version in my laptop, and could never ever go back to having a worse graphics card.
FSX and the older ones work great, pretty much put the sliders up top and still have a very playable frame-rate.
Seems to help with everyday stuff too, my system has never crashed since unless you class a little driver error it had with XP which is now patched. Works with Vista flawless and i have noticed not difference from XP to Vista with it, 3DMark reports a little lower mark with Vista than XP but its so marginal its not worth worrying about.
I have had ATI, and would recommend NVIDIA over them any day, plus the card works with DARWIN(OSX10) and drivers are out there for Linux/Solaris and the likes.
If you go to the NVIDIA Support site, there is a place where you can select your graphics card, then a game and it will report the FPS and a few other details, very worth while...