In iTunes, export to mp3 format and backup to cloud storage. Then you will have local copy and cloud backup.
Slick Deals via Tiger Direct has a 5TB drive for $129 after $20 rebate.
Wow, 5TB! I wouldn’t be able to resist the temptation to “save to file” the entire internet ;’)
Seriously, if you managed to fill that thing up and occasion arose to transfer the entire contents to another 5TB I wonder how long the file transfer would take?