I use LaTeX myself (Usually pdfLaTeX or XeLaTeX) which probably isn't what you are after.

The learning curve is fairly shallow to start as you can produce some very nice looking documents with very little effort using templates ("Packages" in LaTeX speak). If you want to go beyond the basics of using a template, it gets complex fast though. Also some people can't get over that initial "It's not WYSIWYG" thing.

It uses a completely different data model from Scribus, In Design, etc so converting is pretty much a no go.

Still, you might want to give it a look. It gives you some serious geek cred if nothing else.