This looks a good 3TB desktop HDD for the money (USB 3.0 as well).
Interface: USB 3.0
Disk Size: 3.5 Inches
Powered by AC Adapter Cable (included)
Voltage/Power/Frequency: 100 to 240VAC
System Requirements: Windows XP / VISTA / Windows 7 • CPU with 750 MHz or faster, 10MB system hard disk space, 256MB system memory, one free port of USB 3.0 or USB 2.0
Dimensions: 4.2cm (W) x 12.9cm (D) x 16.7cm (H)