As the proud owner of an Archos Jukebox Recorder 20 (a European company who has been making disk based music players for longer than most of the American companies), I have to recommend the Rockbox project. This is an open source replacement for the OS that runs on the Jukebox. It replaces the OS running there and provides everything from longer battery life for verbal menu selections. It is the existance proof of the benefits of an open source project -- benefits to both the company (more features, better support) and the customers. I use Rockbox and I send them my donations -- it's worth it.