I'm a Windows developer and, I have to say, I think it's a great platform. I've developed on and for other platforms. Nothing has the same high-quality tools, especially for GUI developers. Silverlight/WPF are amazing and, I also have to say, they aren't going anywhere. Sure they may be renamed, rebranded as WinRT but that technology isn't going away any time soon. LINQ is a dream to program in and after using it, using a language that doesn't support LINQ is just depressing. What's keeping me on Windows? Why would I go anywhere else?