Exactly how much data storage per month are we talking about? At my work, we have a paperless system tha thas been in place since 1995. We scan every piece of paper that goes through finance. We have 1 full time and 2 part time scanner clerks. They do nothing all day but scan. After 11 years, we're just pushing past the 60Gb mark. That's without ever purging anything from the system., even though we can, by law, drop everything over 3 years old not relating to personnel records and not involved in an active lawsuit.

My backup regime is simple, On the first of every month, I burn to DVD the last 3 month's images and do a full dump of the database. This way, I always have 3 copies of any particular image. All stored on different parts of the respective disks. Since it's running on a linux server, we have a clever little cron job that does all this automatically at noon on the first of every month. I just have to remember once a month to pop in a new blank DVD. It's kinda hard to forget since the tray with the freshly burned DVD is open the next time I walk into the server room.