A few things came to mind just now, and I thought I'd see what your thoughts were. Currently, Mediawiki.org is trying to produce public domain Help pages. Unlike the manual, which is geared towards wiki and server administrators, the help namespace is designed to be for the end-users and contain information on how to edit/search/use the wiki. The pipe dream would be to one day package these into MediaWiki itself in an initial installation. What are your thoughts on this? Also, as a source of content for our (rather sparse) Help namespace...could we turn to the English Wikipedia for some guidance? It certainly has a more comprehensive help section (much would be out of scope for most wikis, however).
Topic on User talk:Zakgreant/MediaWiki Technical Documentation Plan
User docs/help should be distributed with MediaWiki – there's little point in making every installer jump do this same small task. For now, I'm focused on the developer docs, but I suspect that I'll be tasked with working on the user docs in the future.