I've concluded that designing a wiki is as much if not more complicated than designing a web page.
I'm afraid I'll have to agree there; I've realized that my initial hope that the wiki will be self-organizing from the start was actually quite naive....
The best way I've found for designing a useful wiki is to look at other wikis. Wikipedia is an awful example I think. But its so famous that people who want to add content are motivated to learn it. That is not the case in most offices. But there are many other wikis to look at and get ideas from. One of my favorites is www.cookbookwiki.com.
I agree, Wikipedia really isn't the best example in terms of structure. I realized this when trying to pull some content from their help section for use in our wiki - that almost made my head spin! (Disclaimer: I love Wikipedia and couldn't live without it.) So I'll definitely take a good look at cookbookwiki.com - thanks for the tip!
-- Frederik