I couldn't live without it today (Score 3, Troll)

Even as a Windows user, I'll be the first to admit that even a standard word processor like Word leaves a lot to be desired when it comes to creating a document that'll display correctly everywhere (even across different versions of Word). Adobe has done some excellent work with the PDF format, it's just a shame that it's another company-controlled format, though at least much better than the Word .doc!