Today I stumbled upon the Rockbox replacement firmware for the latest iPod models. It has some really cool features, like crossfade support and support for a lot of different audio formats such as Ogg and FLAC. Unfortunately it does not support video playback and I couldn’t find any information if they expect to support it in the future. As expected it doesn’t support music purchased from the iTunes music store, because of the DRM.
I have a 5G iPod (aka. iPod Video) so the lack of video playback makes Rockbox that much less interesting. But if they add decent video playback in the future I’ll be sure to try it out.
Back when I had my 4G iPod I did try iPod Linux for a while. It dual boots between Linux and Apple’s stock firmware, so I could test it when I felt like it. However, back then iPod Linux didn’t have power management among other things, so it wasn’t really an option for daily use. I haven’t checked much up on the support and new features since then, but it has probably gotten more advanced over time.
You can find more information on the Ipod port of Rockbox at their wiki.