In my opinion, I'd stay away from Toshiba HDDs when it comes to Wii USB loading ( if that is your purpose ).
Several models are reported to be incompatible, I myself have a 500 GB Canvio 2.0/3.0 and it only gave me problem from the start ( I have to unplog it everytime I start up the USB loader otherwise my Wii will freeze ), no matter how many revision of D2X I tried.
If I were you, I'd go with a brand proven to work flawlessly, such as WD od Seagate.