* For large organizations, domain controls make managing a large number of desktops much easier.
* I feel MS Office on windows is a better product than the mac version (if you do a lot of document work).
* Gaming. Windows is still dominant for desktop games.
* Windows isn't the walled garden that Mac is going towards.
* Backwards compatibility. Software written 10+ years ago for Windows still has a good chance of working on Windows 8.
* Familiar. People are used to it. I'm not going to force my parents to learn a Mac and all the weird behaviors that go with it.
* Isn't tied to hardware only made by Microsoft (which makes hardware a commodity).
I'm sure there are a number of other points I'm missing, but it's the ones that I like. But there are a number of things I really dislike about it:
* It's not unix based. So the filesystem layout differs, I can't share perl/bash scripts as easily across them. / vs \ for filesystem paths. EOL characters in ascii files.
* It took too long to get a good command line. Powershell is nice, but just too different than what I'm used to with Bash that I get on OSX and Linux.
* Many developer tools today are becoming OSX focused. Windows has a lot of great software still, but many of the smaller nitch tools that I discover are OSX or Linux focused.