sorry for the rant.
yeah man, you are basically talking about 10 years ago.
in the computerworld things can change in months. doesnt matter what adobe did some years ago, now their software is basically pc-orientated. they are concurers of final cut, dvd studio and the new foto-thing apple just lounced. with hardware for exampla, the powerbooks have been noticable slower with older technology then a centrino laptop for more than 2 years now. now finally the intel-macs are coming, so now they are equal. (high resolution screen, "airbag" for the harddisc, all stuff that IBM laptops had years before the macs.).
software wize windows XP finally is not more unstable anymore than OSX, who is saying that? has been truth 5 years ago, but its over. proof it, its an urban myth.
Im performing live with my pc with windows since 4 years now, also art festivals where I was jamming 3 days 10 hours a day, creating music live, recording it at the same time, live/cubase/reason/wavelab running, and you now what? No crashes, no problems. the only bad time was LIVE5.0. - 5.02, dropouts all the time.
so coming back to the first post, I'd say its a matter of taste, nothing more. of course OSX is really cool, and basically smarter than windows, but then open your ableton liveset, and what do you see? your ableton live set.
so I dont spent too much time with my operating system. my choice was for an IBM, because they are build more ergonomic than a mac (trackpiont), and they are modular (I can easily replace my dvd burner with a newer one, or use the slot for an extra hard disc, just with a "klick", without rebooting. thats so far ahead of any mac...).
the last 2,1/2 years, before the intel powerbook was there, it was also a matter of power (much faster pc laptops for a lower price).
cheers
IBM T43 1,8Ghz Centrino (10 Months old)15"SXGA 1024GB RAM 80GB HDD
WinXP/ Live 5.03