I agree that ergonimics is important, especially in terms of hardware. For developers, hardware is screens and keyboards, and pointing devices. As for operating systems, window managers etc., I couldn't care less. I basically don't use the OS while developing. I launch one app and that's it.
I'd go so far as to say that if my IDE would run on only one OS, then my professional machine would simply run that OS. And I'd be fine with it. If I'm using XCode today but Visual Studio tomorrow, I'd be happy to switch. The IDE matters, the hardware matters, but the OS not so much.