Nintendo: Increase production ASAP, pay more for the components if necessary. Invest insane profits into developing more first-party games in all genres -- get the most talented developers out there. Appoint a Guru of Third-Party Development whose sole job is to obtain as much third-party support as possible so that all the best games will be available on Wii. Give him the resources he needs to make that happen. Make sure third parties have all the tools they need to create online games for the Wii.
Microsoft: Make the 360 hardware as reliable as possible and reduce its noisiness as much as possible. Replace all failed system components with newer, more reliable components, and scrap the old products. Gather market research in Europe and go after that market hardcore. Immediately cut the price of the 360 to $249/299/379, and plan for another price cut in time for holiday 2008.
Sony: Honestly at this point, I wouldn't change much. Keep the price coming down, advertise the crap out of the big titles in 2008. Get that TV tuner ready so your PS3 can be a DVR. Keep the existing customer base happy and loyal, and stop publicly making an ass of yourself to everyone else (fire PR if necessary).
