I'm struggling in deciding what usb drive will work the best with the configuration usb loader. I only need 320gb at most. What is the best brand. Would this hard drive be OK? Western Digital Elements 320GB Portable HDD http://accessories.us.dell.com/sna/product...3-404255-124566 Does it matter if it's usb powered or ac adaptor? I feel like it's better to be ac adaptor but who knows. Any recommendations? thanks!