No matter how big ipods get, I always manage to have more music (and now movies) to go beyond its capacity. I guess it's one of those things where you will always find enough crap to fill any space you have. Or maybe Apple is just stalking me an trying to make me buy another ipod.
When your ipod can hold everything you have, life is good. You just plug it in, everything is copied, playlists are maintained, and you don't have to think about it. But once your library gets larger, the auto syncing design breaks down (at least for what I want to do).
Basically if i have a 30gb iPod and 35gb of music, I want to fill my ipod with as much stuff as I can. iTunes does this now by creating a new playlist for your ipod that holds just enough to fill it, and only syncing that. That's fine if you always shuffle your songs, or browse artists and albums, but you've lost all the other playlists and smart playlists you've created.
Here is the criteria for my perfect iPod syncing:
1. Fill my iPod all the way (this can be customized to be less in case you want some free space to use it as a drive)
2. Always sync audiobooks (it would suck if the itunes/ipod sync happened to skip the book you are listening to)
3. Always sync podcasts
4. Always sync all video (this is fine now since I don't have much, requirements will change later)
Here is what I do to sync my ipod (the setup)
1. Create a new Smart Playlist
2. Define it's characteristics as "not an audio book, not a video, not a podcast, etc", limit size to 5gb, selected at random
3. The 5gb size is what I use since I have 35gb of media and a 30gb ipod. You can experiment with different sizes for yourself. The total size of your library is shown at the bottom of iTunes. If you want to leave empty space on your iPod just make this size bigger
4. Name this playlist "stuff to not sync"
5. Select this new playlist and command click on the checkbox to the left of a song. This should uncheck all the songs in that playlist
6. Go to ipod preferences and select "Update all playlists" and "update checked songs only"
7. Sync your ipod
Basically now your ipod is synced with as much stuff as will fit, and all your playlists are maintained. It's possible that your "80's" playlist will be missing some great Depeche Mode because that Depeche Mode song randomly fell into the "dont sync me" playlist, but at least most of your playlist is there.
So now lets say you want to resync your ipod and change which songs are not synced. Easy:
1. Click on the "don't sync me" playlist
2. Command click to re-check all the songs
3. Select all and delete
4. Since it's a smart playlist, it will refresh with a new random selection of songs
5. Command click to uncheck all these songs
6. Sync your ipod!
If you ever get the error "your ipod isn't big enough to hold all this music" don't select the "create a playlist for me" option. It just means you haven't unchecked enough songs. Go back to your "dont sync me" smart playlist and increase it's size.
This works perfectly for me, giving me all my movies and audio books, and a random selection of music. Let me know if you have any problems or suggestions.