I set up all my devices below RAID1 if they are supported. This decreases the disk size below in half, but your devices will handle one drive that fails. If that ever happens, just replaced the drive and it will rebuild itself. You can always change back to the default RAID, and double your disk size.
NOTE: The pictures go in the same order as the list below
Vendor Model Number Device Type Disk Size Interface Connectivity RAID 1 Support Price
Buffalo Inc. HD-HC320IU2-US External Hard Drive 320 GB USB 2.0 / FireWire 400 No (Single Drive) $20
Buffalo Inc. HD-W1.0TIU2/R1-US External (RAID) 1.0 TB (2 x 500 GB)USB 2.0/FireWire 400&800 Yes (Supported) $40
Buffalo Inc. CS-WX1.0/1D External (RAID)/(NAS) 2.0 TB (2 x 1.0 TB) 1 x Gig Ethernet/1xUSB 2 Yes (Added drive) $50
Buffalo Inc. LS-WX2.0TL/R1 External (RAID)/(NAS) 2.0 TB (2 x 1.0 TB). 1 x Gig Ethernet/1xUSB 2 Yes (Supported) $50
Buffalo Inc. LS420D0402 External (RAID)/(NAS) 4.0 TB (2 x 2.0 TB). 1 x Gig Ethernet/1xUSB 3 Yes (Supported) $70
See my link under the map on the right, for other items I've started to post. Will be adding more in the coming week.