Daily I do my work in Windows, OS X and Linux, so I prefer a Mac running VMWare. One computer, one desktop, three operating systems.
I think UNIX/OSX is potentially the better gaming platform actually. Better security, open standards (OpenGL/CL) and so on. One example, running under OS X I can easily switch from my game to the desktop, or put the game from full screen into windowed as I check the web for something related to what I'm doing in the game. The same can be done in Windows, but it's clunky so I don't. I have an iPad handy for that kind of stuff.
It's all a moot point obviously, especially now since Apple killed the PCIe slots.