I don't quite see the appeal of a Mac at this point. I'm spending 30-50% more for a cool looking PC that runs maybe 20% of the applications that are available, and maybe 5% of the games. Yeah, Apple has come up with some really nice features, and it's clear that they have influenced interface design for the better, but what have they done for me lately? Leopard? Who cares? Again, why buy a PC for the OS? Is it more stable? Maybe, but if Apple can't make it stable, they are some seriously crappy programmers, given that they control all of the hardware and drivers involved.
It's my considered opinion that in 5 years Apple will be on their way out of the OS business if not the PC business entirely. They are an electronic device company now, and a damn good one to boot (hence the name change from Apple Computer). Given the margins in the Hardware and software business (all of the $ is in services and consulting these days--never an Apple strongpoint), they are much better off.
As far as Vista, bugs an adoption rates go...well any IT shop that's not run by a damn fool, or someone with their nose up the vendor's butt is gonig to wait for AT LEAST one service pack/patch level before deploying a new OS or major software package. It has little to do with Vista's lack of compatibily with existing software, and everything to do with risk management....i.e. let someone else take the downtime finding the bugs.
FWIW, I run Vista Ultimate on my machine at home, and at work, and while it's not perfect (USB device issues), it's pretty nice, and it's a little bit faster than XP on the same hardware. Of course it eats more memory, and that's where the speed is likely coming from. Oh, and Java is SMOKIN' fast on Vista.
Just my .02