Just as a thought about some of these predictions ...
God of War sold an 'Amazing' 20,000 units in Japan which should indicate that this game will see the vast majority of its sales in North America and Europe; this (effectively) has the game being released on a system with a userbase of 3.35 Million users, the genre of this game is not (particularly) popular, and its quality is not at a level where you would expect a 25% attach rate.
Honestly, I could be wrong but I imagine that a lot of people who read reviews (or hear their friends talking about this game) will choose to rent it or buy it used because of the 8 hours of gameplay which should further hurt sales.
Next week I'd be surprised to see it with more than 150,000 sales in North America and in four weeks I'd be surprised to see it having sold more than 300,000 units in North America.
