I think the Wii U will be compatiable with the Gamecube controllers because the Wii U connects to the Wii, some how. Although it has been forever since I seen it's preview at E3. I'm not honestly looking forward to this system till I see if Nintendo makes any new orginal games besides the rehashing of their classic games. Although I do love them a lot! I'm not touching the Wii U till I see all the other add ons they put with it and I personally think they make another console, in a more traditional sense. That said I really hope the Wii U be much more successful then the Wii and Nintendo learn from their mistakes they've made with the Wii and Gamecube which was no games! I don't just mean 3rd party games either but New orginal games made by Nintendo and maybe some old favorites getting some light in a new way, like F-Zero. Good luck Nintendo!