One of the big missing pieces for video is a JS-visible fullscreen API that players can incorporate into their own UI (e.g. Youtube not having to do lame resize-the-browser-window-kinda-sorta-fullscreen). roc has some ideas on how this should work; I think this is a pretty big requirement for getting Flash parity on video with Firefox 4. Filing this in Video, though it would be nice to reuse most of the code for a generic page fullscreen API.