Do you need to redundancy?
Consider how valuable the data is that you'll be storing. I recently purchased a DLINK DNS-323 NAS device and two Seagate 1.5 TB drives. The NAS is configured for Raid-1 so at least if one drive dies, the data will still be available until I can get a drive to replace the defective one. The array will then rebuild automatically.
Over the last 15 years that I've been in the IT business. I've probably seen about 5 or 6 personal drives die (WD, Seagate, Hitachi) and dozens of others at work.
You still really need to back up your data to something else, at least DVD, which has it's own problems (longevity). I recently bought a BluRay burner. for my media center which is how I store multiple copies of my critical data now.