Last month, Buffalo Technology announced what they claimed was the world's largest portable external hard drive. Now, Western Digital has matched Buffalo's offering with a 320GB version of its Passport portable hard disk drive for consumers on the move.

Weighing in less than five ounces, this 2.5-inch drive works without an external power supply - it's powered by the USB interface - and delivers 480Mbps transfer speeds. It comes bundled with Google software, WD Sync software to make data synchronization simpler, and 128-bit encryption just in case you misplace your drive. If you're looking for portable backup solution with maximum capacity, at $229, this is a great option.