Backing up your iTMS purchases
I usually do a regular full backup once a week (it will be today, in fact), but this time I've also decided to burn a DVD with all my iTMS purchases.
It weighs in at 3.77Gb, so it still fits a single DVD.
I followed this article: Backing up your music in iTunes 4. The only modification I did was ignoring Audible files. With those, my backup would jump to 8.3Gb and would not fit in a single DVD.