This year has been a bad one for privacy minded individuals, with numerous reports of laptops being stolen that contain thousands of social security numbers, medical records and other vital identity information.  It has resulted in a break-neck race by companies who deal with such information (insurance companies, hospitals, the government etc.) to encrypt all of their "at rest" data (Any data sitting on a disk.  Different from "in motion" data, or data being transferred over a network).  In order to make the encryption process as painless as possible, companies look to automated software solutions to selectively encrypt directories and files.  A popular option, since it's free, is the built-in Microsoft Windows Encrypting File System (or WinEFS).  Partial-disk software encryption allows firms to encrypt portions of a disk, without impacting the daily function of office applications and the operating system. 

The alternative is whole-disk encryption.  Which can be software, or some additional hardware on the PC that forces all data on the disk to be encrypted when written, and decrypted when read into memory.  Typically this slows down performance as there is a delay to writing or reading any block of data.  However, this provides the best security and lowest risk.  Partial disk software encryption methods often tie themselves to Windows Authentication to determine access, and NTLM is not exactly hard to crack.

Seagate is currently on track to release its first fully-encrypted notebook hard drive early next year.  The disk contains a chip to handle the encryption/decryption and will refuse to even boot up if the user fails to provide some form of authentication (though what authentication specifically is something to be determined by laptop manufacturers).  Once these reach the market, if their price is right, could become the standard hard drive in corporate laptops across the globe as people are becoming painfully aware of how vulnerable their data has become.