If you have a Windows machine, then you will probably have to go the route you have already indicated.
Alternatively, an external could be the answer here.
If you have a Mac, then get an external drive and let Time Machine take care of all your backup needs
I transfered all 100 gigs of my iTunes library from my old computer to my new computer via home sharing. That's great, I can sync my iPod to the new computer now.
But, when I want to backup new purchases, the new computer doesn't know I already have backups of the old library. It's going to take 22 discs to re-back-up the whole library, because to this computer there never was a "last backup."
Is there a way to get my new iTunes up to date with where I'm backed up, or do I just need to let it burn a whole new backup file?