[PhilD]

More and more of my colleagues (computer science lab and engineering school) use MacOS, apparently. Others use mostly Linux (and system administrators love them for it, since it's apparently soooo much easier to administer lots of Linux machines than lots of Windows machines). Oh, and those MacOS users I'm thinking of are under 50, too.

Personally, I use Linux for anything serious, and Windows for anything that I can't make work on Linux (which included Dom3 until I recently reinstalled a newer Linux distribution, which let me get past the "graphics works slow as hell" problem).