Well, to throw my own $0.02 in, after all this...
Computers are tools.
(Most) users are tools.
The choice of hardware doesn't really matter any more, since the only PC platform now is x86-64.
For most purposes, the software doesn't really matter either. You can get work done with just about any system.
What it all boils down to, for me at least, is openness. Microsoft and Apple have both had a long history of trying to lock everything down to their own proprietary technology.
Microsoft's idea of an industry standard is a specification that only they fully understand, while they give everyone else enough knowledge to be dangerous with. They lock people in by obfuscating the standards so that it's difficult to inter-operate with their data. The data is closed, the system is open.
Apple is better about conforming to neutral industry standards, and built OSX on top of a significant chunk of open source software. However, their entire ecosystem is tied to a closed system -- iTunes. They lock people in by simply making it hard to get your data out of their system. The data is open, but the system is closed.
Those are also pretty much the two approaches that almost every proprietary software vendor in the computer world takes. While we can count on Apple and Microsoft to stick around for a long time yet, what about the small vendors? Some of them develop things like ERP and other mission-critical business systems. What happens when they go *poof*?
That's why, whenever possible, I lean toward using FOSS software. It doesn't always mean freedom from licensing or support costs, but at least the underlying system source and data formats are readily available and (usually) fully documented.
That, more than anything else, is why I use Linux both at work and at home. I also use BSD Unix (it makes a great firewall system). However, it doesn't do everything I need (while Inkscape and the GIMP are good, they're not equal to Adobe products, which means that I'm still locked in by Adobe). So I have to keep both Windows and OS X around. And I'm fine with that. They're just additional tools, after all.