Well.... Nvidia is an ok graphics card. Well supported by Nvidia for Linux is something we may discuss a little further. You will find a lot of documents and help files from Nvidia to get it to work. I've one myself and everything runs smooth and fast, including TV-out and the installation is a breeze.
In another hand, I don't like Nvidia's attitude in making pre-compiled packages only instead of source. They are not really making easier for developers. Have you seem in some games "Nvidia Fog" option? Jedi Knight 2 - Jedi Outcast has it, for example. It should be called "Nvidia Fog's work around". It's because they've changed the fog's distance as from it's standard. If it was open, we could have fixed it a long ago. In fact, they just want to sell their products to Linux users, not truly support them...
Anyway, if you are happy with Nvidia's under Winslow, you will surely be happy with it under Linux. In my case, I've a much better performance with it under Linux
. Prices are nice now to, so go for it buddy