I can't comment on the Tivo or Xbox since I have neither. You can definitely add another drive to your PC (assuming it has room) to hold your music. I would also recommend getting an external drive to back your music up to. I'm paranoid, so I keep backups in three different locations, main PC, network server and external drives. It's overkill, I know, but I used to manage a lab full of database servers where you live and die on your backups.