I do all platforms. I like keeping a Linux for tinkering with and making sure my game builds on it, and while I don't have a Mac I really want one as my next laptop. As a programmer I'm most productive on Microsoft Windows though. Microsoft can do a lot of stupid things at times but they sure know how to treat their developers with the top-dog IDE and great APIs and frameworks that are well designed and easy to use.
So of course my environment of choice to get things done is PC and Visual Studio 2013 as my IDE. C++ for the game and C# for the development tools, with an ounce of Python for the Blender export scripts and eventually some Objective-C for the OS X port when I get my hand on a Mac.
On Linux I just code the old fashioned way with vi or gedit. If I ever need an IDE I'd probably go with QtCreator. Most of the code specific to Linux builds is about interacting with the XWindow server so that's not very complex code and I never need a debugger for that. The OpenGL renderer can be debugged on Windows with Visual Studio.
On OS X I will of course be using Xcode; I'm making a desktop/maybe mobile game so Cocoa/Obj-C it is and I'll probably need a decent debugger since I'm not a Obj-C programmer.
I also tried to mess a bit with Android but I'd rather be flipping burgers than be a Java programmer and the NDK doesn't seem to be working really well on Windows and it requires Cygwin so I guess I'll program on Linux.