I recently went from building high end gaming rigs, to just buying macs, after I got my MacBook Pro.
I have a Mac Pro, 8-Cores, 12GB DDR3, and an ATI 4870, never had a single problem with it. I boot Mac OS X Snow leopard.
I also have a 17-inch MacBook Pro, with 2.93GHz Intel Core 2 Duo, 4GB DDR3
NVIDIA 9600M 512MB, which I boot a LEGIT Version of XP X86 on. No problems booting it or installing steam, or any game for that matter, drivers aren’t really a problem.
With my PC, I had Core i7, X58, 2 4870X2, 6GB of Ram, I could NEVER get Windows Vista X64, or XP x64 to work right ever, always had driver issues from my mice, keyboard, usb devices.
I do programming, and CG art, so the Mac Pro was the best decision I’ve ever made on a computer.
Snow Leopard has ton’s of great free apps, with a great community and developers to fix bugs, and that kind of thing, I haven’t had one single crash, or anything with any of my Apple products.