I wish iTunes and iPhoto would have libraries that are easy to load and unload. For instance, Christmas songs can stay on my computer until Winter, then easily be copied to my iPod.
iPhoto would have a separate library for work photos.
And my iPod & iPhoto would keep the heirarchy of photos from Windows before I got my Mac. (Thousands of photos need multiple layers of photos on my iPod).
I wish iTunes allowed me to get rid of duplicate songs - but still play the two albums that have a duplicate song. The song file is owned by two albums.
Allow me to search for the song "Marion" without pulling up "Funeral March Of A Marionette" as well. (MacIntosh searches default to this, but allow a more specific search).
Allow multiple genres to be selected. For instance, a song can be both "Children's" and "folk", or "Country" and "Rock".
Allow me to create a smart playlist based upon lyrics, or album - maybe of everything that doesn't have an album assigned, or everything with multiple albums, or everything that I have checked as being a song - but which I haven't found lyrics for yet.
When my iPod is synchronized with my main computer, allow me to still sort and select songs from it to play through my work computer.
Sell a safe young children's headphone/earbud.
Make it easy to include my smart playlists, dragging them from iTunes to iPod to iTunes (not the songs, just the criteria).
A utility that shows differences between my iPod and my iTunes.
A utility to show me who's listening to my iTunes - or whose iTunes I am listening to.
The ability to play YouTube videos on my iPod.
Let me synchronize between my #1 and #2 authorized iTunes in my two connected home computers. This means I don't need a normal backup.
Let me check to see which authorized iTunes this computer is using - I suppose an iTunes can be authorized for multiple accounts (on a LAN it listens to songs bought by me or by someone else). Is this computer my #2 account or my #3 account?
Fix the bugs that make it difficult for me to buy a song on my #2 account and bring it home to my #1 account.
When it is possible to upgrade my iTunes store songs to non-scrambled, let me pay for every one I have at once, and convert them.