Yawn. This thread repeats itself everywhere it seems. It's all on personal preference, blah blah... in the end it's what you like that matters, blah blah...
Me? I'm an Apple Fanboy. Don't let that catch you off guard. I still happily play my Call of Duty 4 and tinker with my various BYOSs on jolly-old Windows XP. Hypocritical? Pfft. What, a guy needs to choose one? I love my macs, I love my gaming machine(s), I love my server, I love my playthings. Guess that means I deserve to be shot, eh?
But, as it is, Macs are gorgeous, yet horridly expensive. PCs are awesome, but yet Vista blows out the swazoo (PCs themselves are super, it's the shotty OS that brings it down).
So... there. From an Apple fanboy, who owns Macs, iPods, PCs, and various Microsoft goodies.