Recently, the hard disk manufacturing giant Western Digital announced that it has achieved 520 Gb/in2 areal density in an actual demonstration using its own perpendicular magnetic recording (PMR)/tunneling magneto-resistive (TuMR) head technology which is the highest till yet. For those of you who are counting, that makes it the highest density ever reached using continuous media. A density of this magnitude produces a 3.5-inch hard drive storing 640 GB-per-platter and single hard drive capacities as large as 3 TB. Compare that to the current leading density of around 200 Gb/in2 being shipped high volume products like WD's 250 GB Scorpio(R) 2.5-inch drive. That's all well and good, but you will have to wait for quite a long time to get your hands on this technology. Current estimates put the release at around 2010. That's a huge time in this inddustry but the estimated sound impressive. Well for now waiting is the only option.
Till then play around with your existing hard drives. lol :)