LOL, what's next 360 or PS3?
I've used Windows since 3.0 right up to 7, it does the job but can be a hassle to get everything working together sometimes. I'm pretty sure you'll reply to that statement with "well it's always worked fine for me" but hey. OS X compliments the selected hardware, and works. Plain and simple. Vista also works brilliantly on the MBP allowing me to run any game I played on my gaming PC with no probs.
Rather than lipping off your mate's new purchase, how about taking advantage of your friendship and sitting down in front of his Mac to see what all the fuss is about before trolling forums trying to stir up a fanboy riot.
edit - ah, I see you've stepped down a bit.