NPD seems to think that the PS3's new $299 price point could have a particularly big impact on Sony's numbers once next month's sales are tallied up. While it's obviously not a sure thing, NPD expects sales of the PS3 to jump between 40% and 60% over the course of September, noting that "the USD 299 price point is important to getting to a point where the next segment of price-conscious consumers can jump into the market and it most certainly will re-energise sales of the platform." It's also quick to point out, however, that those sales might not be enough for Sony to take the lead in US console sales for the month, adding that "other systems might too take a price cut," and that "content is still the key motivator of a hardware purchase decision."
Update: Joystiq offers a clarification from the original quote that, historically, price cuts tend to lead to a 40 to 60 percent increase in sales over the previous, higher priced month. The group is not specifically predicting PS3's sales, just pointing out what's happened in the past -- it's a subtle but important difference.