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?

posix systems tend to have much better tools and documentation included in the base system for developers to use while on microsoft it's harder to find

personally i'm a professional programmer who prefer to use bsd as a platform but i can't deny the money in knowing how to write for windows, in my country it's your main source of income, most programmer don't even bother learning about unix or unix-like system if they simply want to make money and a career in this business, just learn c++, c# or java and start hacking away on graphically bloated programs for idiot clients