It depends on a lot of factors, but I see this holiday season looking something like this:
America:
A price cut to $299 will likely result in sales about on par with the 360 or slightly ahead. When the PS3 only cost $50 more than the Xbox 360 premium back in early 2008, it was consistently outselling it slightly. With the PS3 priced at the same price as an Xbox 360 premium this fall, I can see it outselling the 360 by an even better margin. There's not a whole lot Microsoft can do to counter this, either. Sure, they can bundle and reshuffle SKUs, but I don't expect any real price drops to the system. Their software lineup is good for current 360 owners, but when it comes to new buyers the PS3 will appear as a much better deal overall.
Even with a price cut on the PS3 (and no price cut on the Wii), the Wii will edge out the PS3 this holiday season in the US. However, it could be closer than we all think if the Wii continues its slide and new software fails to induce sales like Mario Kart or Wii Fit did last year.
The PS3 has a good software lineup this fall in the US, but Sony won't have a mega blockbuster exclusive that sells multiple millions in the US alone. GT5, if it releases, may have a shot at that, but I believe this is GT's weakest market, and consequently the market that GT will face the largest competition from Forza 3.
In summary: Wii > PS3 >= 360
Europe:
Europe is a different animal entirely. If the UK sales figures are accurate, then the 360 has outsold the Wii in the first half of this year...and substantially so (by 300k, IIRC). The Wii has appeared to drop considerably in this region, while 360 sales have remained high. This is good news for Sony because if they drop the price and release GT5, then they should easily push a LOT of units in the UK and mainland Europe, and unless the Wii has a dramatic shift in the coming months, it'll oddly enough be the system that sells the least.
Software wise, GT5 is a gigantic seller in Europe. It's GT's strongest market and it will push systems. There's also the fact that the PS3/360 pricing disparity is larger in Europe than anywhere else, I believe, so when Sony moves on price then they will have a huge momentum shift in the region.
In summary: PS3 > 360 > Wii
Strange turn of events indeed if this comes true...it'll be like the inverse of the start of this generation.
Japan:
Depending on software releases, Sony could see the PS3 well above the Wii for the holiday season. If GT5 and FFXIII release, then there's no question the PS3 will consistently outsell the Wii even if it did not receive a price cut. Earlier this year the PS3 was doing just that in Japan alongside the help of key software releases. GT5 and FFXIII are bigger releases than anything they had earlier this year. WITH a price cut, and a new hardware revision, I think the divide will be fairly large.
In summary:
PS3 > Wii >>> 360
Overall:
This prediction is based upon a number of key assumptions; namely that the PS3 receives a $100 price drop to $299 alongside the Slim model and that supply is not considerably restrained. If the price drop is less, and/or GT5 doesn't release, then the impact will lessen depending on the region. However, it seems very likely at this point that Sony will target the $299 price.
If Sony can keep up plentiful supply of PS3 Slim units, then it wouldn't surprise me at all to see them capture 2 markets this holiday season (Japan and Europe), while trailing behind the Wii in the third (USA). Overall, the numbers could be quite comparable (worldwide) to what the Wii sells and it may even manage to outsell the Wii, as crazy as that may sound. But Sony will ultimately have a very strong Holiday season and see a large momentum shift in their favor.
