Well
tbh, I am with Abaxas here. Windows doesn't have POSIX compliance unless you install the very clunky Cygwin. Stuff like PERL and bash, apache etc all come as standard. Admittedly you CAN install them into Windows, but it's an after thought.
Linux on the desktop, for me, still isn't there. I'll admit it's great as a server OS, but it's quite simply not as polished as OSX or Windows. I quite like the fact that I can fire up iChat/Skype, and it just works. No messing about with settings, ndiswrapper or whatever, it just works.
I can set up a photo package. I can set up VMWare/Bootcamp/Cygwin/ActiveState PERL etc. I can build my own PC with whatever components I want. I've done it lots and lots of times, but I can't be arsed any more. I'd prefer to go into a shop. Pay a bit of a premium and walk out with something which:
1) Looks good
2) Is well specced
3) Is very tightly integrated
My iPad failed within about 3 months of getting it. The charge/sync port on the bottom just stopped working. I walked into an Apple shop (a different one from where I bought it) and handed it over, and (after messing about with it for 10 mins or so) they handed me a new one.
You can argue that it shouldn't have failed, and I'm most certainly with you on that, but try that with a Dell, HP, Compaq, Alienware, IBM etc etc. You simply can't as they don't have a high street presence.