i just backed up my entire itunes library (12 gigs). I then re-formatted the HD. i copied all the tunes back into itunes. now, my question is, as i start to add more albums and want to backup again, how do i keep from dupliating what i already have backed up? The first time i did it, i just created a playlist called backup and added everything to it and burned away (i really liked how itunes automaticaly spanned the dvds). any suggestiona?