As well as plugging feed autodiscovery in his "10 top tips for your website" session at IWMW2008, Mike Nolan suggested that institutional web managers check out that their "Page Not Found " (HTML error message 404) page were in some way useful for their users, for example by including a site search box or 'did you mean?' links.
So for the sake of comparison, here's a preview of 404 page thumbnails for a range of UK Government Department websites, along with links to any RSS feeds that are autodiscoverable from the Department homepage.
(See also: How To Make a Great 404 Error Page & 10 Examples.)
About: 404 "Page Not Found" Error pages and Autodiscoverable Feeds for UK Government Departments