<div style='font: 10pt verdana; text-align: left; padding: 0% 10% 0% 10%; '>Unix based OSes are heavily used in academia, particularly for research of various kinds. When people network 100 machines for parallel processing research, they're not doing it under Windows.
The Unix paradigm is also extremely important theoreticaly (i.e., provide a very small set of basic system calls and build higher level libraries on top of them).
Unix based OSes generally have the best free tools - for programming and for other tasks. Yeah, Visual Studio is a fantastic programming environment, but g++ is a better compiler in general. (Conforms to the standards closer - this I have first hand experience with because of the undergrad research I did last semester. Visual couldn't even compile most of the stuff we had.) After installing Linux, depending on the type of install I did, I can immediately start developing for C, C++, Lisp, Perl, Fortran and other languages I can't think of.
I like Windows. I'm using it right now. It's easier to get things working under Windows - mainly because it has larger support. But Unix based OSes are generally better programming and research environments.</div>