Quite recently I decided to undertake a major private project: Taking a large body of RPG-related books (I.C.E.'s classic Rolemaster, 2nd Ed., to be precise), re-editing it (making one concise rule volume instead of a set of base rules and lots of optional add-ons) and translating it (to my native German). The goal was to provide a rule book that my friends and I could use for a RPG campaign.
That's a good dozen books of ~100 pages each, to be compiled into a ~300 page 4-part volume chock full of tables, lists, charts etc., with hundreds of cross-references to chapters and tables, footnotes and graphics.
Another requirement I placed on myself was to make the result look as much as the original as possible - including the two-column layout, typesetting, chapter headings etc.
Previous experience told me that neither MS Word nor OpenOffice Writer would be up to a task of these proportions and still be maintainable.
I've heard about LaTeX before (from co-eds at university), and decided that this was the time to give it a try.
Being a professional software engineer, I like learning new (or, in this case, old) technologies, widening my skill set, and actually prefer doing things "in source" as opposed to "WYSIWYG". (Being able to
svn my work sounded like it could come in really handy given the scope of the work, and I was absolutely right).
I downloaded the basic LaTeX package, the Texmaker editor, and a "quick guide", set up a SVN repository for the
.tex files, and went ahead. It took me less than a day to realize that LaTeX was the ideal choice for a project like mine. Especially the fine control over tables impressed me, as well as the ability to enter the table data right away and worry about the actual layout at some later point.
I ordered the LaTeX Companion the next day. Took me a couple more days to find your excellent site here, though I ask myself what took me (regular customer at StackOverflow) so long.
I can't say I'd use LaTeX for everything, or even for most things. But for my project right now, I couldn't imagine anything more adequate. Too bad I won't be able to make it available to the public once I'm done. :-\