I think PS3 will get to 5 first. Final Fantasy XIII + White FF13 PS3 bundle will bring more hardware buyers than New Super Mario Bros. Wii or Wii Fit Plus, even though I think NSMB Wii will sell the most software in the long term.
Nintendo has lost their momentum in Japan with the Wii ... I would not be surprised if the price cut has only a minor impact there. I think the PSP price drop will overshadow the Wii cut in Japan.
They will have to regroup next year, likely banking on that Wii Vitality Sensor to become the "next" Brain Training type fad.