The latest browser releases from most major players (except Microsoft of course) now support the new HTML 5 video tag, including Firefox 3.5 and Safari 3&4 which means that video just works without requiring a plugin. Of course not everyone is running these browsers (yet) so what is required is a neat way of using these new features where possible and yet gracefully fall back to using Flash, Quicktime or Windows Media in the event the features are not available.
Ideally of course you want all this to happen without browser sniffing or other such nastiness that will just store up problems for the future. Well the good news is that all this is possible using HTML without any Javascript. How? Check out Kroc Camen’s Video For Everybody page for all the gory details.
Here is an example using the source code from camendesign.
Download Video: High Quality “MP4” | Low Quality “OGG”