I also stand by the "more choice is better camp".
I use AIX, Tru64 , linux etc on work but most of my home "desktop" env still runs windows (or is dual boot - except from my Mac G4 system ).
Why? It simply does the job quite well (and my windows desktops *are* as stable as my Linux system - sorry ) and I already have the licenses.
I'm not saying Mac or Linux or better or worse, they are different and that's the beauty of it.
Thankx (mainly) to the GNU/opensource movement there is nowerday's almost *always* a choise, and even in the case where it's not 100% what the "closed" counterpart offers, if that he "closed" counterpart pisses off enough users it won't take (to) long to have a full OSS replacment.
Fed up with vista but is Linux not "your thing" ? Join http://www.reactos.org/en/index.html and make it stable before XP is like NT3.51 now.

The day's a company like Microsoft really can "dictate" a market *completely* without a counter reaction are over imho. Wich of course does not mean they can't provoke a mess