I have a 500gb external usb drive that I use for my iTunes library and for backing up my internal HD. I was thinking about making two partitions, one being the same size as my internal drive and using that partition for backups only. I would have to move my iTunes library to my internal drive temporarily to do this, but otherwise it would be simple. Is there any real advantage to this or is it just as good backing it up to a folder on my 1 partition?