What happened to the copies on your computer in the iTunes library? If
you deleted them there you have misunderstood how the iPod/iTunes works
- i.e. your media resides in iTunes and is synced to your iPods. Not the
other way around (due to stupid anti-piracy provisions in the contracts
the record and movie studios have with Apple).
As well as understanding iTunes and the iPod you should invest in a
decent backup solution. At the very least keep your original CDs in a
safe place, or better yet backup your iTunes library using both local
and off-site backups, e.g. Time Machine in OSX 10.5 and CrashPlan
If you're not part of the solution, you're part of the precipitate.