The Register reports that Seagate is offering a massive 4 TB hard drive for $250.
Seagate brags that the drive can store 2,000 high-definition movies, thus answering the question of what you need such a large drive for.
The unanswered question is who has time to watch 2,000 high-definition movies. At a rate of one per night, it would take me 5.5 years to get through that library, which is likely to be longer than the drive would last. Maybe some people watch more movies than that. But it still seems like an awful lot.
But beyond that, I’d be afraid to just use the drive as, you know, a drive. That’s an awful lot of data, and how do you back it up? Perhaps a second 4 TB drive. But if I actually had 4 TB of data at home–I don’t, not by a long shot–I’d be more comfortable storing it on a RAID array instead, to get some redundancy going. Because disks fail. And that warranty just replaces the hardware, it doesn’t get your data back. Combine five 1 TB drives with RAID5, and when–not if, when–you lose a drive, you can just swap the failed drive and you haven’t lost anything.
The best use I can think of for a 4 TB drive is the backup device for a large RAID array. In fact, it wasn’t even a week ago that one of my old classmates asked what you back a 4 TB RAID array up to. It took me six days, Neil, but I think I have your answer.