Some other driver stuff:
When Forceware 75 (now quite old) was released, I got quite a significant performance improvement in Nexuiz. I think this was because of the OpenGL 2.0 support.
In general later drivers are better but not every official driver is good on every machine. I don't use the latest 87.56 under Linux because for some strange reason it limits me to 1024x768 in everything.
There are also some drivers where they break support for older hardware without realising it. For example, Forceware 60 series and later will not work with DirectX on machines with 64Mb RAM or less. They don't say that in the readme since their minimum specs are complete rubbish. Luckily OpenGL support doesn't seem so finicky.
The chance of getting a bug fix from nVIDIA in a driver is rather slim unless you're a major games developer. I have pointed out to them that the desktop context menu for seperate displays does not work under Win2K and nothing has been done for over 2 years. It works under 98SE, it works under XP but not 2k. So if you do find a problem with one of their drivers, forget it. Either put up with it or use an older version without the problem.