I think some of you have the wrong idea...
OS X blows away Windows in terms of luxury... It looks, feels, and acts better bar none. It is a beautiful OS, and it has put the fun back into computers.
Sure, you could go out and buy a $399 pc, but big deal. It's not as nice to use as OSX.
Plus, many users have an extra monitor lying around (old CRT) so why pay $$$ for flat screens, when they are at a premium? Especially if you already have one?
I use a PC, and I program in C# / VB.Net. Windows is the better of the two for application development, bar none. But it stops there. For pure fun, OSX is it.
And when Mono gets going, you'll be able to do that on Macs as well.