I'd like to see more audio formats supported. For one reason or another, Quicktime can play/rip AAC, iTunes can play it, but the iPod can't. The confusing part is that Apple is pushing it as the successor to MP3, but you can't use it on their MP3 player. Also, lots of people are looking for Ogg Vorbis support.
Apple, the iPod Isn't Finished!
After the Mac: Keeping Apple Innovative