Why install this driver?
Your NVIDIA video card will work on your Fedora 11 box without this driver, however if you want to enable the 3D acceleration (if you want to use Compiz Fsuion) you need to install it.
Which driver to use?
The latest nvidia driver: This is a proprietary driver that works with newer nvidia cards.
The legacy nvidia driver: This is also a proprietary driver, but it works with older nvidia cards.
Current list of Legacy NVIDIA drivers: