Go buy a 2TB for $65 on eBay.
For Wii U: Plug it into the back port(s.) If it has an A/C adapter, the top one will do fine. If you need to use a Y-Cable because you have a pocket-sized hdd, use both back ports with the data cable on top.
For vWii: Running homebrew applications such as WIIMC (though I HIGHLY recommend setting up a PLEX Server instead and running through the Wii U Internet Browser in 1080p) or even homebrew games like WiiCraft, use a 32GB SD card. If you have a lot of movies and TV Shows, use your hard drive using the aforementioned setup depending on the hdd you are utilizing.
It is really that simple.







