I've been charged with building a documentation system/platform. 

Here's a short list of the major requirements:

* Easily localized : This will need to support a dozen or so languages out of the gate. (the ability for non-technical personnel to add/update translations would be a big plus, though not 100% required)
* Flexibility in output formats : At the bare minimum, I need to output the documents (either as a whole or in selected chunks) as PDF and HTML. Bonus points for native formats like Windows Help Files.
* Managed and deployed via an intuitive user interface (web, ideally).

I'm wondering if you folks know of any systems out there that support this type of thing already? I'm not averse to writing this from scratch, but I'd rather not reinvent the wheel if I can help it.

The two major candidates I've come across thus far are [DocBook](http://www.docbook.org/) and [reST](http://docutils.sourceforge.net/rst.html). The former seems to have garnered a reputation for, well, sucking. I'm unfamiliar with either, but I'm told that reST would get me a good portion of the way there.

Any other suggestions? Would I be better off building this from scratch?