Text is still king---or at least "evil overlord". Over on his Fastware
blog, Scott Meyers (of Effective C++
fame) has been explaining why he's writing his next book in LaTeX: it'll handle cross-referencing, can generate every output format he cares about (PDF, HTML, etc.), and plays nicely with version control. The last is (for me) the most important: I'm in several collaborations right now that are using Microsoft Word or OpenOffice for documents, and since version control systems can't diff or merge concurrent edits to them, we're having to play "pass the baton". I posted a plea to the Google Summer of Code mentors' list yesterday begging people to propose projects that would teach their tools how to play nicely with version control; we'll see what comes of it.