This player (based on the JW FLV Viewer) can manage FLV (Flash Video), MP4, MP3, and AAC. It can also easily "pull" videos from YouTube. I have the option of hosting the video files on YouTube, the COTM server, or the Mosso Cloud server (my favourite as it is both dirt cheap and lightening fast).
Because it's dynamically generating this material from a single playlist, it is much simpler to do updates than my previous, manual methods. I'm pleased.