The nouveau driver does a reasonably good job on my GTX 480. With the proprietary driver and nvidia-settings, I was able to get the temps out for my conky, and of course that is not possible now with nouveau. Desktop effects work, more or less -- no "cube switching" or some of the other advanced 3D effects, but it's fully usable with 4 virtual KDE desktops and separate activities for each desktop. Googleearth is kind of semi-functional if started in "DirectX Mode" in lieu of "Open GL Software Emulation". But it crashes about 30% of the time, and has to be started in a terminal, not krunner.
The nouveau driver is getting better and better, I agree with that
I have have problems with gaming and mythtv
If I didn't do the 2 above, it would be standard on all my boxes