A 500GB desktop hard drive is quite handy, and is still somewhat impressive. It's soon being overtaken by even larger models, though, and nearly every HDD manufacturer has an affordable 500GB offering. What's more impressive? If they can shrink it down to 1.8” form factor. Fujitsu has announced the development of a technology that lets them get data densities as small as a Terabit per square inch. Interestingly enough, this was accomplished by mixing some components of optical technologies with existing magnetic technologies:

The process integrates optical elements as part of the manufacturing process for the hard drive. A lens is used to focus an extremely tight beam onto the magnetic platter. The beam heats the platter which allows easier recording on the magnetic media. Using a specially designed optical element, Fujitsu was able to attain a spot size of 88nm by 60nm with 17 percent optical efficiency.
Imagine having a 500GB iPod, or a laptop with 2 500GB HDDs in the space you formerly fit a single 2.5” in. Release dates for drives using such a technology haven't been made available, and nor have potential capacities. It sounds incredibly useful though.