I have a WD NAS drive 2tb at home, and a buffalo 2tb with shock protection for the laptop.
I dont consider either of them to be a good solution though......
I would get two raid 1 systems, and back one up from the other as and when I needed to. Run one of them normally on a decent surge protected system, and have the other powered off and unplugged.
For example, for something that I cannot replace and that I care about (ie family photos) I have copies on several HDD at several locations. I back those copies up everynow and then manually.
meaning that if I have a fire at my main location, I have a backup that is normally only 6 months out of date at another physical location.
They are stored in Pelican cases.
Call me paranoid, but I dont want to lose over 15 years of digital photos.