If the Wii didn't outsell ps3/xbox360 combined I have a really hard time imagining a console outselling their two competitors combined to be honest. (I know it happened during the 6th gen with ps2 but I dont think it will happen again)
I think the Xbox 720 is a safe bet. I'm pretty sure they will suceed since I think M$ is doing everything right atm IMO. They have the kinect bandwagon, insane amount of entertainment app, known for best online and I'm sure they will find a way to make their next console with the perfect balance of price and power. But don't forget that they can barely sell 1000 consoles a week in Japan, and I dont think it will change in next gen.
Wii U imo is a big ? for me and most ppl. It could do really bad or really good. I think it will do good imo. Nextbox will probably be first in NA but Wii U will probably be first in Japan. So I think it will be close between the two.
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