You might also take a look at
Windows Home Server, which manages hard drives similarly to Drobo. Pre-built WHS boxes from HP (EX478) are around the same price as Drobo's.
WHS' built-in backup/restore capabilities are extensive for those using MS Windows computers. FULL image-based backups of up to ten PCs are made daily. You can restore any of those ten PCs quickly and easily. WHS manages the backups so you can restore from many dates, varying from yesterday to months ago. You can restore a single file, a single volume, or an entire PC.
I haven't used a Drobo, but looking over the manual, it seems that Drobo doesn't actually do backups of PCs. It appears to be a storage device only, with built-in redudancy and disk management. WHS does both storage and backup, plus several other features like web site hosting, remote PC access, and media serving to various home media devices.
You can also build your own WHS server, which, depending on your choice of hardware, starts at $100 for the WHS software itself. Pretty much any existing six-year-old PC can be turned into a WHS with the addition of one or more big hard drives and a DVD reader for loading WHS the first time. If you choose to build your own, WHS can also re-use old hard drives of any type with a suitable drive controller.
Whatever your decision on backups, congrats on deciding to do something about them. Losing your data to a hard drive failure is
so '90s.