Freedom anyone ?
I think there is something missing in most of the commentaries, some of you will call it the political bias but in fact it is mostly a philosophical one.
This all Linux thing is about freedom, freedom of choice mostly, that is why if you choose to run windows or os X, it is fine with me and with most of the community, I agree there are zealots, but then you can find them everywhere.
There are so much uninformed comments in this thread, it is difficult to debunk them all, I'll just try to adress two of them:
First of all, unless you want the latest drivers from NVidia, they will be available in your distribution's packages, you will just get a message stating that since this is a proprietary driver, the community will not be able to support it.
The second one is about the support you can get, in fact it is second to none, most of the participants are willing and able to help you even on very technical subjects, of course it will be very easy to find a lot of counter-examples, but most of the time the problem comes from the user unable to ask the correct question: "My sound is not working" is not very indicative of the problem, so there are further questions which are asked and responded to.
I understand perfectly that coming from a Windows background, some people expect to just put some kind of drivers disc in the cd-rom reader and click next a few times, but it just does not work like that in Linux; either all your hardware is detected and functionnal straight out of the box (so to speak) which is the vast majority of cases, or you have to digg a bit further and then the community kicks in and will resolve most of your problems.
There are also some material which just don't work at all under Linux, that's why there are huge hardware databases which will tell you wheter your material is supported or not.
But once again all of this is about personnal choice, if you feel more confortable with Windows or OS X that's fine, if you want to take the Linux road it's fine also.
A final note I run 150 seats all under Linux (thin client based with RDP access to the few remaining windows applications) all by myself and none of my users has any technical background (we are a local government administration), how many windows sysadmins would be required to do the same with fat clients? I don't really know but my gut's feelings is : a lot more!
Have a nice day