- Equalizer. I would love an equalizer setting that is optimized for sonic quality, with some presets to optimize the use of different types and brands of headphones. Each headphone has some colourations, and therefore it might be nice if the iPod can compensate for that. Being able to load your own equalizer settings would be great as well.
- Playlists. Playlists are displayed on a per-song basis. It would be very nice to have an option to display a list on a per-artist/album basis (i.e. add the same hierarchy as you have for Browsing: Playlists->artists/composers->albums->songs). I use playlist to store new albums, or albums I tend to forget to listen to, but it is difficult to find an album via its song titles only.
- GUI. Going hence and forth from a setting action to the music playing is quite a traversal. It would be nice to be able to access a menu directly from the place where a song is playing, that can be customized like the main menu. A customizable hot-key combination would be nice as well (e.g. pressing forward and backward simultaneously would set it in Shuffle mode).
- Adjustable backlight. The amount of light emitted is quite strong, and probably consuming quite some battery power. When I'm listening music in bed before sleeping, my girlfriend even wakes up from the amount of light emitted.
- Security. If you mount the iPod to another computer, it asks whether it should remove all the files. Scary, especially if friends are playing around with it, and press "Yes". It must be able to "lock" or "password protect" the iPod for such cases.
- Playlist. Be able to manage playlists on the iPod as well, including moving, sorting and deleting albums or songs.
- Delay between songs. A zero delay between songs is not possible, unless you record them like that beforehand in iTunes. A programmable delay between songs would be great.
- ID3 tags. Be able to display other ID3 tags as well, like the bit-rate, playcount, last played etc. Also be able to sort/browse files through these tags as well. (BTW, extend the browse capability of iTunes with a composer entry instead of an artist entry for classical music would be great as well).
- Mounting. It might be nice to be able to set/reset the desktop mount feature on the iPod itself, instead of via iTunes only.
- Connecting. Don't stop playing music when the iPod is connected to the computer.
- Formats. Add support for WMA and OGG.