It had been a difficult problem to compare Windows and Linux. I had been holding the idea that in the Unix world, people write small and simple programs which work together via standard linkages like pipe and other inter-process communication mechanisms. However, under Windows, people tend to write a huge program which can do everything.
An example is word processing. In the Windows world, we have Microsoft Word, which has a huge number of functions: editing, rendering (WYSIWYG), spell checking, printing, and much more. However, in the Unix world, we use the TeX system, consisting of many programs, each does one simple thing — TeX macro defines basic typesetting functions, LaTeX defines more, Emacs (or any other editor) edits, pdfLaTeX (and other converters) converts sources into PDF or other formats, AUCTeX or Lyx implements WYSIWYG, and etc.
Well, by mentioning above, I think I am not so bad as I see at least the Separation and Composition philosophy of the Unix world. However, there are many more that I have not been able to summarize. Anyway, the lucky thing is a master had summarized them for us, so, please refer to the great book The Art of Unix Programming.