USB 2.0 to IDE Cable
 

USB adapters for ATA (a.k.a. IDE) devices are useful things. If you find yourself in need of hundreds of gigabytes of portable storage that you can plug into pretty much any computer you come across and, assuming it's a reasonably recent computer running a reasonably recent operating system, Just Use It without installing drivers, then USB-to-ATA adapters are about as close as you'll get.

USB adapters will also let you turn a basically worthless old medium capacity drive (20Gb or less) into carry-around storage which beats any expensive little laptop-drive or Flash memory alternative. Bulkier, yes, particularly when you include the AC adapter as well as the drive itself (USB power's only good for 2.5 watts, which isn't enough to spin up most desktop drives), but you can't beat the price.

http://dansdata.com/usbadapt.htm

Nice tool to have around the house or office.;)