Identify theft and the value of protecting personal data is on people's minds more today than it ever has been. The fact that laptops are small, relatively lightweight and unbelievably easy to steal makes that even more of a problem, coupled with the fact that you can get 500GB of storage into a 2.5 portable drive not much larger than a cell phone. Hence, a lot of vendors have been trying to put people's minds at ease by offering off-the-shelf encrypted storage. Buffalo is the latest among them, expanding their MiniStation drive to include a line of self-encryption portable USB hard drives.
The units, with capacities up to 320GB, aren't all that special compared to any other drive. However, Buffalo will be offering the drive for nearly the same cost as a standard drive, showing that putting stock encryption onto a drive has very little cost. This is assisted by the fact that large manufacturers like Seagate and Western Digital are making drive encryption in hardware a standard option on newer HDDs. Once a drive is plugged in, all that is really required is a password cumbersome 3rd-party software isn't required.
I suspect features like this are going to become almost ubiquitous on every home NAS, portable drive and even flash drives in the near future.