Nvdia makes great drivers, awesome drivers for Linux. Those drivers are so great that no one has been motivated enough to write a good Open source driver for it.
OK, I'm kidding, there is a good Open Source driver for Nvidia cards already but they only support 2D functions. So if you want 3D hardware acceleration, you have to settle for the official driver. So whats wrong with that? you might ask.
Well if you are a Linux user, you might have come across the inconveniences involved with of upgrading the Nivida driver or the Linux kernel. But thats really a minor price to pay, compared to the freedom lost as a result.
An year or so ago, Nvidia dropped support for some of their old graphic cards such as the Riva TNT2. The result - you either had to upgrade your graphic card or use the last driver they put out. Chances are that last driver doesn't support any of the recent kernels. So your also stuck using an old kernel. Your freedom to keep up is lost.
One of my friends had an Apple PPC notebook (a really expensive Powerbook) which had an Nvidia card. He decided to install GNU/Linux and all of a sudden, there is no (3D) driver for his graphics card. Nvidia doesn't think its worth the trouble to put out a PPC compatible binary driver for Linux as most Apple users' run MacOS.
There are just some of the reasons why its healthy to have an Open Source Nvidia driver which supports 3D acceleration, thats good enough to run a 3D desktop such as XGL/AIGLX. Thats why I made the following pledge:
"I will pledge at least $10 USD towards the development of the
open source nouveau driver for the nvidia card series but only
if 1,000 other people will too."
If you believe in the cause, you too can pledge (no you don't need to enter your credit card just yet). If anything, it motivates the developers who are working hard with no official support from NVidia.