Toshiba's MK6465GSX sticks another 140GB on top of the previous limit of 500GB. The downside is that the drive runs at only 5400RPM, which means if you want it fast you should look elsewhere.
The drive comes with an areal density of 817.9Mbit/mm2 and the family of which it is the big but slow daddy will come in 640GB, 500GB, 320GB, 250GB and 160GB models.
Toshiba provides a drop sensor option to help protect the drive should the host system be dropped, or the aircraft you are travelling in encounters turbulence or plummets from the sky.
The big drive is also being released as an external storage line for those who like their hard-drives in bright colours. That USB-powered drive ships in Liquid Blue, Vivid White, Rocket Red and Komodo Green, and it should be available now for $180.
As for the internal drive Toshiba is not releasing an asking price but should be shipping it to OEMs in the next month or so. Since Toshiba ships to Dell, HP, Acer and Asus, among others, you should see this drive as an option if you are buying a machine for Christmas.
Quite why you need to carry 640GB of data around with you, particularly if you want to clear US Customs without a search, is anyone's guess.