The problem with coming up with an absolute number is that we lack certain key data to come up with it. The most significant piece missing is the eventual lifespan of the systems on the market. And even with that, we still lack the critical data of what tactics the companies will employ to steal the limelight from each other. To wit: the PS3 and 360 have traded sides in being the "dominant" second place runner up 3 times this year, each time due to a slight adjustment in tactics (price drop, carefully timed release of a popular game, new SKU released, etc.).
Without such key data, the best we can do is state which is currently "leading" as second place, and possibly speculate vaguely on who will ultimately hold the title. The odds clearly favor Microsoft at the moment, but they were clearly favoring Sony 3 months ago. And they could just as easily be favoring Sony again 3 months from now.
Sky Render - Sanity is for the weak.
