My current storage (RAID-1 off of a hardware RAID card) and backup (a spare drive) solutions for my home network are inadequate. I have too much data scattered on various one-off drives. It is time to evolve. Backups seem simple enough, at least: lots of big drives. However, I am bewildered by the number of choices for small home storage. The Drobo S looks appealing. So does the ReadyNAS. I am not looking for bunches of shiny features, I'm mostly interested in reliability. I am not interested in building Yet Another PC to create a file server or doing something in the cloud, or whatever. I'm stupid, so I am keeping it simple.

Requirements for Main Volume:

1. Starting working space roughly 2TB, with options for growth up to 5TB
2. RAID or something RAID-like with at least one parity drive
3. eSATA II for speed during backups
4. Ability to shut down gracefully when alerted of low power by a UPS
5. Optional but Desirable: Will take 2TB drives now with options for the larger 3TB drives coming in 2010-2011
6. Optional but Desirable: : RAID-6 or something similar, with two parity drives
7. Optional but Desirable: : Hot spare
8. Ethernet connection not required, as the volume will be shared via the same machines which runs my home print server

Backups:

1. Backup performed via ROBOCOPY in mirror mode to an external hard drive via a eSATA II connection.
2. Start with rotating between two external 2TB hard drives, will go up to six external 2TB drives.
3. Start with a weekly backup, move to a bi-weekly backup as more drives are added.
4. Move to 3TB drives as the size of my main volume increases.
5. Backup drives will be stored on an off-site location.

Hard drives:

1. I plan on buying all of the same model, but different batches from different vendors.
2. I found a "burn-in" utility with which I can pound away on the drives for a couple of weeks before adding them to the backup pool or the main volume.

I estimate that I am looking at roughly $1,500 to start, once I start throwing in two TB drives for backup and four for storage. So, are there any obvious flaws in my plan? What have I overlooked? Any suggestions for the storage device for my main volume that fits my requirements? Or do I just keep it simple, 2 drives in RAID-1, then perform due diligence with my backups, accepting that I will have to buy a whole new unit when my data grows past 2TB?