Happy Fish is a great program. I've been using it for more than a year now. I especially like that it can delete a file off my hard drive when it sees that I deleted it on my player.
One feature that I would find useful, would be the ability to set a filter that would stop unwanted downloads (my podcast player will only play .mp3 or .wma but some podcasters include weird things like .mov or .mp4 in their feeds). So if I could filter the enclosure by file name or extension then I could block these downloads. Or, alternatively, a filter for synchronization would also work. Then when I connect a player that can do video, it will get video files, or a player that only does audio will only get audio files.
Thanks,
Tokr