Linux vs Windows: What do programmers use.

I was woundering if it is a common theme for most "Pro" programmers to use linux. I mean a book called C;Programming I have was written on linux. So which OS is it that programmers or hackers, per say, use?

When I realised my final year university project was going to involve a whole lot of programming I finally got around to downloading and installing Linux because I find programming in Windows to be really unpleasant. Linux was built by hackers for hackers so it's hardly surprising it provides a much nicer development environment. Windows was originally a crude hack to make DOS somewhat usable.