LaCie, WD MyBooks, and similar "box" externals: I don't like em, had too many fail and too many friends that have had them fail and lost their data. I think one makes a decent Time Machine drive if you're on a Mac, but that's about it.
DROBO: It is pretty much idiot proof, but is somewhat slow -- I have the FW800 version and get about 50MB/s max sustained transfer writing to it or reading from it with 3 or 4 drives (RAID-5) mounted, and that drops to 30MB/s with 2 drives installed (RAID-1) and have heard that if connected to the Gig-LAN adapter it runs at about 30MB/s max. Read more on my DROBO experience here, including my "idiot" torture test of yanking and reinserting drives:
http://forum.getdpi.com/forum/showthread.php?t=2560Alternative: I like this screwless 2-drive box and would consider it as a simple solution over a dedicated RAID array or DROBO if money were a concern, however you still run into the issue of combining adequate redundant onsite storage combined with additionally redundant offsite storage:
http://eshop.macsales.com/item/IcyDock/MB662UEAB2S/ My system: Working image files stored on a RAID-0 array on my Mac Pro for very fast reading and writing; then backed up to a DROBO (RAID-5) onsite which is scheduled and run by Carbon Copy Cloner -- and as back-up I don't care how fast or slow it is, just like the fact it is RAID-5 redundant; then the files are further backed up to individual bare drives stored offsite also using CCC which automatically runs when the offsite drive is connected. I use this device to write to my offsite drives:
http://eshop.macsales.com/item/Newer%20Tec...ogy/FWU2ES2HDK/ and store those drives in these nifty boxes:
http://www.wiebetech.com/products/cases.phpHope that helps,