Well first of all. Excellent choice on picking up one of the best games (perhaps the best) of the year.
I would go Wii U. HD, Miiverse, and a variety of very comfortable controller options.
3DS does offer 3D, and a cool streetpass mode, but it will be lest comfortable, and not HD. Also, 3DS won't be getting the multiplayer update that the Wii U and PC are getting.
PC doesn't offer anything exclusive. It's the last version I would buy.