I prefer Mac OS but unlike many other Apple users, I have no intense dislike of Windows. I just like OS X better. I think Windows does some things very well but in my specialized field, it's a little easier to work with a Mac. There's a stronger support network.
In my limited experiences with Linux, it's a far bigger hassle than I care to deal with. I prefer to do work on a computer, not work on the computer itself. Besides, no Photoshop, no deal. I can't do anything without that program (first person to mention GIMP gets a slap in the face with a dead fish, there's no comparison).