I doubt that they will see a boost from E3 and I don't think its a majority view that they won it. Did they have the best news and biggest story? Yes. But its clear to me that much of the rest of their presentation was found average or only okay by many.
For example EGDE game E3 to Sony: http://www.edge-online.com/features/we-review-e3-big-three?page=0%2C0
They may well get a boost from 20GB stock clearance, but when big games like GTA IV and price drops in Europe only give moderate boosts at best the news an exclusive game went multiplatform and is likely 12 months from release isn't going to drive any new sales IMHO.
No one (or too few to matter) is going to buy a 360 and wait for FF to drop. Those who bought a PS3 for a 360 may whine about the change but they're not going to buy a 360 because of this, they'll still get FF on PS3.
Does it make 360 look better? Sure, but on its own its not going to drive anything much IMO.
Try to be reasonable... its easier than you think...
