Default simple interface
Concept: Greatly simplify the interface for new users.
See also Default view of content.
Basic ideas 
Reduce the number of links in the nav-bar, particularly those not useful or comprehensible to non-editors.
Add one or two links suitable only for users who have never interacted with a wiki before (including a single-click "turn on advanced interface" link to restore the current interface).
Make a friendly "comment on this page" link more prominent than the "edit this page" link -- "edit this page" is, surprisingly, intimidating and confusing to some (perhaps many) new users.
(Once we have gotten a user to use an edit form, be it for a talk: page or for an article itself, they may be much more likely to be hooked and to find out about editing in general.)
Target user-groups 
- The media, coming to find out about our project; stats, About: pages, contacts.
- One-stop users, visiting a deep-linked specific page. We should encourage them to click on another link before leaving, without overwhelming them.
- Visitors who have heard there are ways to contribute to Wikipedia, but have a hard time with the "edit" concept -- encourage feedback from them in familiar ways.