>>8
>well maintained XP machine
And how many well maintained XP machines do you know? The thing is, Unix in general highly encourages and simplifies keeping one's system clean and well maintained. Software installations are neatly seperated from the OS itself and you can do almost any kind of work without needing super user access or needing to tamper with any operating system components.
On Windows... well, there are reasons why so many people still work with administrator accounts all the time. It's a fucking pain otherwise. And even today one installation of a piece of software can crash your system or at least make it unstable (registry, system32, etc). It's ridiculous how much effort is put into confining the huge mistakes they made when designing Windows. Look at Vista's all new fancy security features, UAC, various system file recovery facilities and all that shit.
Most, if not all Unix systems run longer and more stable without any of those, given a reasonably intelligent administrator (not giving away super user passwords, etc). To reach that level with Windows you'd have to restrict a user's access so badly he wouldn't be able to get any work done. As for me, I'll just run linux, install vmware, show our guys how to use the snapshot feature and we're fine.