This is why I like commercial backup programs like acronis true image (this also backups partition and disk images - but that's another topic).
(
Backup software for data backup and disaster recovery in Windows and Linux - Acronis)
Select backup data -- select the files you want and point to your new drive
Choose NO Compression then it will copy the files as they are quite quickly.
If you choose compression copy to a "Staging device" ( i.e any spare directory) and the choose Restore to your new disk. Now you've got a backup copy as well -- perfect.
(Added -- if your Ipod is recognized as an external disc you can "backup" files to this as well - choose NO Compression. Note this doesn't alter the compression of the music files if they are already compressed. It just copies the source files to the target Ipod).
Cheers
jimbo