Emacs, emacs, eeeeee-maaaaacs, to use LaTeX. But then you wouldn't be using Windows! :) I'm writing my thesis in LaTeX - there's just no way Word could handle it.
I will, on occasion, use OpenOffice, but it's a bit unwieldy too.
Pine for my e-mail - no viruses ever get through totally text-based mail software...

Seriously though, I've been working in this Computer Science department for over 3 years, and although some people use Windows (the rest of us are on Linux or Unix) everyone knows better than to send anyone a Word Doc. I cannot for the life of me understand why people would want to attach one to an e-mail. either it goes in plain text, or you send a PDF. Rant ends!