One day, the hard drive as we know it will be completely dead, replaced by local cache memory and storage on the internet. Until that time comes, however, you will have things like the new LaCie CloudBox.
This hard drive gives you the usual local access to your data and automagically backs it up to the cloud, with no user intervention. It actually saves the ten previous versions of every document, so you can go back in time. The offer seems quite good: When you buy the 100GB drive, you get a year of 100GB online storage. LaCie says that prices start at $200.
It sounds great on paper. I'd like to try how it goes through my 60,000-image iPhoto and 60,000-song iTunes library.