500 GB Portable Hard Drive USB 2.0 - $55

Features:

Aluminum case for cooling the hard drive
USB 2.0 with transfer rate up to 480 Mbps
Plug & Play without rebooting
Compact design

Is actually an Western Digital Scorpio Blue 500 GB Bulk/OEM Hard Drive 2.5 Inch, 8 MB Cache, 5400 RPM SATA II WD5000BEVT drive with an external enclosure

The enclosure: http://www.amazon.com/Vantec-NexStar-2-5-Inch-External-Enclosure/dp/B002JQNXZC/ref=sr_1_1?s=electronics&ie=UTF8&qid=1342311767&sr=1-1&keywords=hard+drive+enclosure

The drive: http://www.amazon.com/Western-Digital-Scorpio-Drive-WD5000BEVT/dp/B001JSSDGU/ref=sr_1_2?s=electronics&ie=UTF8&qid=1342312111&sr=1-2&keywords=500+scorpion+blue