The need for storage space is never ending. Since the era of the first generation hard drives which had to be transported via trucks, the hard disk drive technology has improved by leaps and bounds. Storage devices have now become smaller, lighter, faster and more powerful. With the USB interface gaining wide acceptance, external hard drive that are plug and play have become very common. We take you through a list of 7 best external hard drive that you can think of owning as a backup device.