IMO, the biggest mistake first-time ipod owners make is allowing iTunes to sync music, because it creates problems like the OP.
To prevent this from happening again, please:
- Plug in your ipod.
- Open up iTunes.
- Click on your ipod icon (it’s under “Devices” on the left).
- Click the “Music” tab.
- Uncheck the “sync music” box.
- Repeat this for every category (pictures, podcasts, movies, etc.).
Repeat for every computer the ipod may come in contact with.