I spend 85% of my time in Linux, running Beryl-svn with Avant and Kiba. The nvidia driver support is better than "good".
Beryl is not exactly stable software, but I have very few problems that last more than a day before one of the Beryl folks corrects it. And, it kicks Aero's backside from a thousand angles at one.
This is posted from my development machine (Ubuntu/8800GTX w/EK waterblock/9746 driver). See how fast it displayed on your end?
I can boot Ubuntu Edgy, Suse 10, Redhat EL4, Vista Ultimate, or XP. I stick mostly to Ubuntu because it provides the best of everything. I run Windows only when I need to test something that requires a non-virtual Windows environment. I even play the linux UT2004 from Ubuntu without any problems.
What's not to like?