Honestly I think in the higher end market, Microsoft is going to drive Sony out in the next 5-6 years by creating a better piece of hardware, which in turn will make them the console of choice for "hardcore" players.
Sony can't afford to price match Microsoft anymore, and Microsoft knows this. A couple of years of losses upfront on the 720 and they can bury Sony for good. We're starting to hear some reports that seem to indicate MS is "going for it" at the urging of some developers (probably Epic and some others). So I could see a situation where the 720 has say 4GB of RAM + a beefier GPU versus a Sony Orbis that has 2GB RAM/weaker GPU.
Nintendo will retain a good portion of the lower end/"normal person" (lol) market, but MS will make inroads here too with Kinect.
