http://www.buffalotech.com/products/...n/terastation/
The 2 TB model is now available for about $1,000 online.
It can be operated RAID5 meaning you have 1.5TB of usable storage and the other .5TB is used for striping and mirroring. If one of the 4 hard drives fails, the other 3 are used to reconstruct all the data. You can immediately start using the drive, but data from that "dead" hard drive will be slower to access as it is reconstructing.
And it's 1000Mbs (gigabit) Ethernet, so you can put it in a separate room from your computers.
I intend to get one soon, so all of my data is stored externally from my computer, so if my computer crashes, it has minimal impact.