stax,
Well I don't know if you are like most of us, but we generally have 2-3 large drives with 20-50% in use. As you have 5 I assume you are utilizing more of this space than most users.
I would make efforts to organize yourself, to the best of you capabilities. And not just Kiss this off as I can't. It will benefit you professionally as well as personally. A bit of well placed organization will pay benefits in time saved.
While not specifically a backup solution, you might consider setting up your storage as an RAID 5 Array. I take it you are concerned about losing the information that you have. RAID 5 provides for data redundancy and if you lose a drive though failure you can replace it and the data will be rebuilt. This differs from your current state where if you lose a drive you also loose the data contained thereon.
This could be deployed in your current case with the addition of a Raid Controller card, or another possibility is a "Network Attached Storage" device; NAS for short.
Buffalo makes a good device that can be populated with dives to achieve 1.6TB of storage.
Buffalo NAS
Tape is not a particularly difficult operation but is somewhat slow. There is a convention (organization) for effectively excecuting backups though.
Quick Overview: A full backup is generated. Daily incremental backups are then run that only backup changed information.(usually much quicker) and then weekly a full backup is done. Tapes are then rotated. For a 200GB drive using compression there will be 1-3 tapes with a low end tape drive. There are tape drives that have higher capacities and higher initial cost that could contain 200GB on one tape volume. Tapes are also expensive.
Drive Example
None of this is specifically thrifty. But one must ask themselves what losing a large block of data would cost, If the data is critical you can employ the services of a data recovery firm and this costs on the order of 1-3K US. Not cheap but again if the data is needed & there does not exist a backup???
As I think this is work related, data preservation is not usually a difficult sell. One must just present the facts of what it would mean if data were lost.
Article on Tape with good reasons
Sorry that I have no really cheap solutions for your situation.
rvnguy
"I know everything..I just can't remember it all