The people at LongTail Video, who put out the JW Player, have done an excellent job in the past couple of years of navigating the Flash video vs. HTML5 situation (check out HTML5 Video: Not Quite There Yet). The reason for this post today, though, is that latest version of the JW Player can be set to prefer HTML5, and fallback to Flash when necessary, or prefer Flash and fallback to HTML5. This means that you can reliably serve videos on your site using JW Player, knowing those videos will play reliably in Web browsers and in mobile devices (e.g., iOS devices that don’t support Flash). Getting our Web sites to work reliably for all (or almost all) users is the hardest part of being a Web developer; JW Player’s work in this regard is most welcome.
The JW Player has all sorts of other features, including skinning (already mentioned), support for plug-ins, and the ability to work with different delivery mechanisms (CDNs, Flash Media Server, etc.). If need to provide video on your next Web project, I’d highly recommend you consider JW Player.