I have a old Nvidia card that needs the nvidia 96 driver to enable all the fancy compiz effects (the noveau free driver doesn't work). I tried installing it with Ubuntu Software Center but it said that it had dependency problems.
As long this is an open bug, you can try the open-source driver Nouveau. To enable the experimental 3D support for this driver, you need to install the package
Although it says experimental and is still unsupported by upstream developers, that driver works pretty well on a lot of Nvidia cards.