Personally I feel quite indifferent when it comes to preferences for operating systems. E.g. I do most development work under Windows, but our J2EE server solutions run on Red Hat. I have to deal with the respective OS APIs at times (and I appreciate both of them), but I care more about programming languages, framework libraries and IDEs.
My son Alexander though seems to favor Linux, which may be due to the fact that Tux is such a cute mascot.