The Wii U's eShop represents a big step forward in digital distribution for Nintendo, with eShop-only indie titles sharing shelf space with downloadable versions of major retail releases from day one. These larger titles can easily occupy over 10GB of space, with Tekken Tag Tournament 2: Wii U Edition confirmed to be over 16GB.
Whether you picked up the 8GB Basic console or the 32GB Deluxe version, chances are if you dabble much in downloading you're going to want to expand your available storage sooner or later. Luckily, Nintendo's made it easy to augment the Wii U's onboard storage with USB hard-disc drives (HDD), and Nintendo Life is here to walk you through the process and help you get the most out of your new Wii U.
It's tempting to get a 1tb hard drive from amazon when it's only $65..
It's USB 3.0 (but all 3.0's can be used on 2.0 ports).
That and it has the power cord so you don't need to worry about there not being enough power.
They also have a 1.5 tb for I think the same price, but USB 2.0.