greggles showed me how to make a view show different content to different users by role the other day, so I thought I'd write it down.
The goal: Displaying different nodes to administrators than I show to just authenticated users and that different than what anon users see. (In this case, I'll show pages to administrators, stories to authenticated users who are not administrators, and articles to anonymous users.)
The strategy: Create three different displays in the view, each of which is limited to a particular role, and each of which has its own filter. The administrator display has a filter that chooses pages, auth user one that chooses stories, etc.
The devil's details: The displays must be ordered by most restrictive to anonymous. The displays are apparently attempted in the order they're shown on the views edit screen. So we need the most restrictive (administrator) first. On that one only administrators will succeed. The next display has the authenticated users, etc.