Upgrade issue, no music shown on iPod, 30G of space still taken

After upgrading both yesterday, I went to play a song on my iPod to find that it said I had NO songs. Plugged in iPod to sync to library, but said that I had 30G of "other" that I can't delete or edit and that there isn't space to sync my music (because it is already taking up 30G on my iPod, but can't access it). Most of my music is from non-iTunes sources (CDs or MP3s from other providers).

I don't want to completely wipe the iPod (unless it's the only option) because a couple of the other apps have content that I regularly use and that is still accessible.

Any suggestions?