Gotta go Mac. Or in my case MacPro. Better, faster, you can swap out parts contrary to popular belief, has a FAR better OS. Downside, not many games. Then again I have a Playstation and an XBox. The few computer only games that I find worth playing are also available for Mac.
And yeah, just the way it runs and the way Apple thought about how the interface works and should work is YEARS ahead of what Windows is capable of. Want to see how Windows will (kind of) run in 10 years? Look at OS X now.
OS X - Sleek, well thought out, easy to use, easy to customize, and if you want it you can get down to command line level.
Windows - Crashtastic, weak clone of OS X without the well thought out part, constantly resets itself and settings for apparently no reason, BUT you can play a shit load of games.
OS X is to Windows, like the iPhone/iPod is to Zune. Theres just no comparison.
Of course thats just me, I'm a different bread of cat. Kind of like DDKR!!!