That's not my experience, I'm afraid.
I had 3 similar AMD64 multi-core PCs, all of them with NVIDIA GT440 cards in them, and for over a month now I've been trying to get them to work with the proprietary NVIDIA drivers that are up in the v295.x range - I cannot get any of them to start an X-session at all, and since about v173 of the drivers, there's been a problem that when they did work, if you logged out of the X-Session, you'd get a black screen with a few white dots and dashes in the top left corner with a total machine hang.
Incidentally, I dropped an ATI card in one of the machines, jiggled about with the kernel a bit, dropped in the proprietary ATI drivers and an accelerated Gnome desktop fired up fine. (Nope, I'm not an ATI fanboy by any means, there are BIG issues with their drivers on Linux and always have been.)
I have managed to get accelerated desktops working on the NVIDIA machines using the open source "nouveau" drivers but they, of course, are still reasonably early in development and give nowhere near the framerates of the proprietary NVIDIA drivers under normal circumstances.
The worse thing about it is that I used to own an NVIDIA GT-250 card that worked flawlessly under Linux but sold and replaced it with one of the GT-440 cards. I have since discovered on a forum (though not sure of the truth of this) that the only real difference between the GT440 and GT250 is that the former supports DirectX 11 whereas the latter does not, which is of course irrelevant to Linux.
Incidentally, if anyone can recommend me a reasonably good NVIDIA card for up to $100 (I don't need bleeding edge cards, if it can run Fallout 3 or Fallout New Vegas then that's fine for me) that also works well under Linux, I'd be grateful. I've lost touch with graphics cards specs over the past few years and when you check out reviews and comments on the Interweb, there's always a lot of conflicting information given.