I have a tnt2 riva card and according to the Nvidia website. There is no support for the newer Xorg. I think their answer to when is "someday". Unless you need 3d support, just use the open nv driver. I could not see any difference in performance in Mint 5 with nvidia vs the nv driver in mint6 RC1.
With tnt card you will get funny resolution choices in the xfce display settings tool.
You need to add explicit depth and resolution settings in the Screen section of the Xorg.conf.
I am at work now so I can't post the exact stuff I used.
Otherwise all the default "configured" stuff works in the Xorg.conf seems to work.