Confluence (http://www.atlassian.com/software/confluence) also has the ability to export to Word (feature description: http://confluence.atlassian.com/display … d+document). Basically, on any page of the wiki you can select and option to "Export to Word" (or export to PDF).

More interestingly, we have a free plugin called the Office Connector that allows you to work back and forth in Word (and Excel & PowerPoint). You can create a Word document, format it, add photos, etc., then with one click you can import the document into a wiki page, formatting and photos and all. And it goes the other direction too. The advantage is that people that prefer MS Office can do their work on their desktop, then share it and collaborate on it via the wiki. There's a video of it in action here: http://www.atlassian.com/office. It currently supports .doc, we're working on adding .docx support.

(Full disclosure: I work for Atlassian.)