Autover plugin will automatically version your CSS and JS files in the generated html page (e.g. style.css?ver=1359464809).

Load one Theme for a specific user. You must set the theme from User Profile then logout and login again in order to take effect.

Generate a mapping of image - article it belongs, by scanning all attachments.

Site protection plugin for dev instances to avoid indexing by search engines. Doesn't allow access to the site without being logged-in.

Displays the most visited posts as a widget using data from Google Analytics. Designed to be used under high-traffic or low server resources.

Convert all your database character sets to utf8, trying to follow Codex guides.