LaTeX on Mac OS X
I used LaTeX when I was in school to create reports, presentation (using beamer) and even sometimes class notes and assignments. Recently when I was looking for a presentation program in Linux I was crestfallen by the lack of polish in OpenOffice Impress. So I created my presentation for the Salt Lake Linux User Group in LaTeX and it looked professional (nothing surprising there). But that was created on my tiny Netbook running Meego....