Wait, I thought I already posted in this thread. Guess not.
OS X for general computing on a laptop (word processing, media, web browsing, occasional media production), Windows 7 on a desktop and for anything else. I think that OS X is a much better laptop OS than Windows, and in any case it works better on my PC laptops than it does on my custom PC. I'm planning on reinstalling Lion on my PC to see whether my new 560 Ti changes the experience any....
Definitely Windows. Windows computers can support many different programs, and they are easy to use. Macs are ridiculously overpriced, and they don't even have a freaking right click! They try to hard to be "minimalistic", but they don't try hard enough to make a well-performing computer.
As the resident Mac user, I have to say that's wrong. While the software library for Windows overshadows that for OS X by a ridiculous amount, OS X does have a lot of commonly-used applications available for the operating system (unless it's specialized software, in which case that's a valid argument). Also, OS X does have right click, just not in the traditional sense. On a Mac laptop, or a PC laptop running a Hackintosh'd copy of OS X, a two-finger click will do the same thing as a right click. Likewise, on any Apple mouse since 2005 (probably before that), you can toggle the software settings within OS X to enable a right click. Besides, any two-button mouse works in OS X with right-click.
The price point is something I'm not debating, though some might argue that the additional money pays for the quality of the user experience (I have to admit that my MacBook from 2008 has the best trackpad of any laptop I've ever used regardless of the year). However, the hardware is very overpriced for the money, I agree. And minimalism is really something perceived in the eye of the beholder; tweak the OS a little (and yes it's possible to modify OS X) with a custom theme and BAM instant minimalism. My MacBook is a black one, so I modified the theme in OS X to have a black menubar, a large assortment of black desktops, black icons, a black Dock, and a black Google Chrome. It looks pretty sleek when everything is black.