I have two. One for Wii U, one for my computer.
The one I have for Wii U is 1TB. I wouldn't have gotten it but it was on sale new for $25, and I really couldn't pass that up.
The one I have for my PC however is 2TB. It has around 1,300 or so GB left. Should last me a few years I suppose.
Actually I'll probably manage to have it full within the year lmaooo