Toshiba yesterday announced the world's highest capacity laptop HDD, the MK7559GSXP. The two-platter drive holds 750GB and reaches the same 9.5mm (0.37in) height as most notebook HDDs.
Toshiba also announced the MKxx59GSM line, which offers users the same 750GB HDD, as well as 1TB option, but both are three-platter, 12.5mm (0.49in) drives.
All of the drives operate at 5,400 RPM and Electronista reports they're due to start sampling for system builders in April. They should enter mass production soon afterwords.