Our servers are all Linux - I don't know if that helps you at all. We just find they're easier to work with and Linux is more stable (ie - doesn't affect the browser in a negative way). Linux is Open Source so there are more free products you can install, scrpits, etc. Linux is also more secure (in our opinion).
If all of your pages are .HTML pages then you can choose either one without issue - your hosting server has nothing whatsoever to do with what tools you use on your computer, what your browser is, what your OS is, etc. so don't worry about that. If you're coding anything in ASP then you will need to choose a Windows server.
I don't know if that helps or confuses you even more....let me know
