Draque is correct.
A RAID setup would help go a long way in preventing data loss.
Then again so does doing backups, but how many of us ever worry about it till its too late?
*raises hand*
One thing to keep in mind: Read the reviews! If a device has as many, or nearly as many bad reviews as good, you may want to steer clear of it.
Caz, what kind of computer do you have?
If you want, I'm betting the techies of the group would be happy to help do a little research in helping you find the best deal.
EDIT++
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136073This would be larger, for a bit more, and a crap to of good reviews vs bad ones.
I'd be a bit leery of re-certified drives myself.
W'raa