One of the main benefits of Joomla 1.6 is the ACL (Access Control List) that has been introduced. This video provides you a visual guide as to what this involves for site administrators. It's a must see for all Joomla users. Enjoy, and thanks to both Andrew's for producing this.
You can see further details on this here: http://www.theartofjoomla.com/home/38-talks/101-the-joomla-16-video-access-controls.html