Fanboys yell a lot, but I think most of us don't have deep feelings such as love or hate towards an operating system.
I find Windows rather annoying, but that's about it. It keeps informing me about stuff I already know or don't care about. If I have unused icons on my desktop that's my business. If the software firewall is off, it's probably because I turned it off. No, I don't want to activate Sticky Keys, and I really don't want to restart every 5 seconds, just as I don't understand why I have to call Microsoft to reactivate, when I play around with the hardware or reinstall on a new computer.
That being said, most of the applications I use are already pre-installed in OS X, whereas that is not the case in Windows. A brief rundown:
1) Latex. OS X: sudo port install texlive. Windows: I'm told it can be done.
2) Grep etc. OS X: preinstalled. Windows: Install Cygwin, but still feels kinda foreign to the OS.
3) Subversion, Java, Ruby, Python, vim, emacs. OS X: preinstalled. Windows: Needs installation.
4) NFS. OS X: works great. Windows: PITA to install and rather slow.
5) ssh: OS X: preinstalled. Windows: Putty is actually almost as good, but needs to be installed.
...No contest really