Well, for a start MS is already somewhat in a bind as the Arcade is already the cheap console in Others and we know how well that went vs Wii and PS3 sales. Pretty much every week the 360 is in last place low Arcade price or not.
In US it likely will drive better weekly sales, particularly due to the economic woes facing that territory right now, but I seriously doubt it will make enough difference vs the Wii and while it may force a reluctant price cut from Sony I doubt it will truly make much difference there in the long run.
MS has improved a lot this generation, but if they were truly hoping to take the number 1 spot this gen and capture the market that ship has already sailed globally IMHO and in many ways I think the price cut is about hanging on to as much US market share as possible in the face of Wii domination and PS3 steady gains.
Try to be reasonable... its easier than you think...









