Now that firefox (v3.5) has built in support for ogg videos, ogg is now the most convenient format for “easy to view” video files (assuming you don’t want to use a service like youtube). Some digital cameras (like my Canon) records movies in AVI format. I created a script that uses gstreamer to convert the AVI file to an ogg file for easy viewing.
http://dev.bec-systems.com/svn/pub/avi_to_ogg/avi_to_ogg
And some of the results:
(hint, download firefox 3.5 to view these videos)