One player that has yet to steal market from the handhelds is Windows 8 Tablet. People will say whatever they want but having a tablet with windows and xbox live integrated into it will entice people to get that instead of a gaming dedicated device. If I could play XBLA games on said tablet I don't see why I would need either a DS or a Vita... and buttons are not a good reason.
Windows, Android and Apple are the way to go imo, Sony and Nintendo needs to come up with something similar.