For documenting code, I also recommend Sphinx. ReStructured Text is nice because it is readable and somewhat marked up in plaintext, and can do a nice job converting to html and to pdf. I still like LaTeX for certain things. My wife and I use LaTeX to write our christmas letter, which we mail out via snail mail. The pdf version is pretty fancy, with two columns, and headers and footers. The html version is simpler. I convert with plastex. Examples here:
http://fedibblety.com/annualReports
I don't think any binary format is a good choice (Word) for any sort of document that you might like to read 10 years from now. That is one of the nice things about LaTeX.