I would suggest [video4all][1]. If HTML5 is supported it uses the HTML5 tags, if not it falls back to [Flowplayer][2]. So you have really man features you can use. On one side the HTML5 tags with all the settings and on the other side you have all the flowplayer features, likes Auto-Thumbnailing, etc.

[1]: http://code.google.com/p/video4all/
[2]: http://flowplayer.org/