I was first skeptical about buying a 2 TB HDD, as I already had one 1 TB HDD. But being a father of little daughter and a hobby dslr photographer, the hard disk space becomes priority. Means not only for storage but also about the backups.
So I jumped in and bought two Seagate 2 TB HDDs with USB - 3. And I am happy that I took that decision. Its since 1 year , both HDDs are working fine. I basically use them for Backups. Connect one to main computer for backup and then switch to other hard disk for one more backup.
Absolute Value for Money in long term