sharke
You can always download it and burn it onto DVD's or even save it on your hard drive. No need to download it again. I have a folder on one of my drives for downloaded installers. Gotta be worth doing to save that box surcharge.
Absolutely. I have a huge archive of purchased/downloaded software stored on a network share on a ReadyNAS. I don't ever touch a box or a DVD. This is so much more convenient.
As far as backup goes, I have a separate ReadyNAS that is a backup stor, with incremental backups taken automatically every week. Then every month I copy that backup NAS off to a USB hard drive that either goes into a fireproof safe or else goes offsite. Everything I do makes its way automatically to those offsite backups eventually.
Every year or two I find a rainy day to go through that whole archive and delete the stuff I am certain I will never use again.