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In terms of money, I would say iPhone, with the Wii U and Kindle probably fighting over second place. In terms of disruptive technology, I would have to go with the Wii U. Both the iPhone 5 and Kindle Fire HD are incremental new models of existing products. Yes, they have superior capabilities compared to their predecessors, and are both interesting and desirable devices, the iPhone 5 more so to most people. The Wii U is different. It may be able to do what Google and Apple have been trying to do with respect to the living room. For those less familiar with the Wii U is uses a tablet like controller that is integrated into both game play and control of other function such as what Nintendo is calling "Nintendo TVii". Really. TVii. Oooookay...
What TVii brings is an integration of ALL of your entertainment streams into one system, at least in theory. According to Nintendo it supports all of the big cable and sat TV providers plus Tivo, Netflix, Hulu Plus and Amazon, and layers on an additional level of information, easily and without any significant effort by the user. So you can access streaming content, chat, see sports plays, etc. while watching any given program Most of which you can do with a laptop, iPad or whatever, but the Wii U does it without requiring that second device to control the actual content. It's like a super-remote/laptop/tablet/controller thingy. On top of that you have the expected internet connectivity for browsing and downloading games, as one would expect.
The Wii U may be a success or may not. I haven't seen one in person yet, so I withhold judgment. But unlike the other two devices mentioned, it does move in a different direction from its predecessor, and has the potential to be the most disruptive technology. I'm a gamer, so I may be a little biased. That doesn't mean I'm wrong though.