This news is a few months old, but it is so impressive that I just have to mention it now. Researchers are working on a storage device with a 1 terabyte per square inch capacity that also has the potential to last more than a billion years (see this ). They do it by using sliding iron crystals in carbon nanotubes (for technical details, see this).
How time flies (remember the days of floopy disks?) I really hope they can develop this technology!