So much stuff going on in this thread it amazes me at times.  There are a few points I want to hit on and then I will be done with it.

My first point is the simple fact that it doesn't matter if the PS3 does slip ahead in a few years.  The damage is done and the Glory of the former King (PS2) is dead and gone.  I would imagine coming into this gen a majority of people would have said that the PS3 would have smashed everyone and easily outsold everyone by a factor of 10.  Over confidence and Arrogance did Sony in.  Anytime higher ups of a company ask you to take a second job  or get a loan on your house to buy their product, something is  wrong.   Even with all of this going on, Sony has managed to lower the cost and find some humbleness (Saving the PS3 and the company).  Hopefully things will change for the PS4 and we will not have this mess again.  If they Jack the price up again for the PS4, Sony will not be as fortunate next go round.

Will GT 5 sell 10 million copies?  Personally I think it will do around 6 for the simple fact that the PS3 doesn't have the user base that the PS2 did, not to mention that base has splintered.  I don't think 1 out of 4 people will make a racing game purchase this gen.  In the states It will be lucky to do 1 in 8.  I know that Europe still loves racing but I don't think it will be as big as a lot of people give it credit for.  The real question is how many PS3's it will sell.  I'm thinking not many.  A lot of those GT lovers from the PS2 have moved over to the 360 and this has split potential sells.  If the PS3 was $199 things would be much different though.

Halo Reach will have about the same impact on console sales as GT effectively canceling each other out.  I do believe Reach will sell several million more copies though.

All in all I don't think there will be a big difference sales wise with either system.  The 360 will motor along for a while in front and then something minor will change and give the weekly sales lead back to the PS3.  This will probably cycle through for the rest of this Gen unless Natal/Kinect really does a game changer.  If that happens all bets are off and the 360 will win hands down.  So while I don't think the PS3 will finish second this gen, the best it can do it will do is a stale mate.

Last thing, I love how a few of you like to cherry pick your numbers to suite your needs.   Too bad there is always someone coming in and pointing those out.  Snap!!

erm, it will do 4-5m just in europe alone, halo reach won't move consoles becasue halo3 and osdt already on the console. its userbase its there.

GT5 its first full GT, prologue did almost 4m? and 39% of GT5 buyers doesn't have even have a ps3.

You seem to understand trends... so explain to me why people buy the Xbox 360 every day? I mean its been out for years and people are barely buying it? Also, both ODST and Halo 3 rank fairly high in the sales charts. Why is that? Why didn't everyone interested in Halo buy those games a long time ago?

Basically I'm saying your logic is wrong. There will be a big sales spike of 360 consoles when Halo Reach hits the market. Neither of us can quite explain why, but it'll happen.

I won't even argue with your GT5 statistic. I imagine that was determined by a small survey and has no validity.

It isn't a significant negative mark on the Xbox 360 if its pushed into 3rd after more than 5 years on the market and it isn't a significant positive mark for the PS3 to win a phyrric victory over it's special olympics running mate in the 'HD war'.

i'm not even going to respond to the GT5 and Halo comments. i an see why Halo wouldn't move any consoles, but as for the first release of 10 to 15m unit selling game like GT5 and it being the first of the series to hit this gen and people saying it won't do anything or is beyond me and makes no sense.

predicting the future (like we do on this site everyday) is fun but a lot of things i see in this thread take things to far and out of context.

i can also see why Halo would move consoles and i can only think of one reason. Limited edition console bundle.(i remember seeing that some where) , but i see mostly current owners picking that up.

See! People are debating Halo Reach vs. Gran Turismo 5 as console sellers. I don't believe I was far fetched in making the claim in a previous thread about Gran Turismo 5 not selling as many PS3s the same as Final Fantasy 7 sold PS1s.

I jumped the shark 1000 miles from shore on this one, but I was not the first and never claim to be as that is a whole 'nother pointless argument in of itself.

Gran Turismo 5 as a system seller....In Europe maybe if the Euro does not take another dive as the world economy is in the midst of a double dip recession as we debate.

Ahh, so you're in the purist camp on the whole debate on system sellers? I.E. Has to show a major boost or its just a blip.

In the context of this discussion, I think the impact of GT5 will be mitigated by the fact that Kinect launches in the same week.  I don't think we'll see much of a spread either way.  I would suggest that the 39% survey taken from a sample size of 1000 are most likely waiting on the console price to come down or else would have been all over GT5 Prologue.

i was waiting for you to show up. i must admit i have a new found respect for you, but none the less i agree.

i'm not sure if either can boost console sells. (i'm more in favor of GT5 doing it then Halo only because it's the first real release in the GT franchise on current gen consoles)

it always seems that sequels boost sells of consoles and sell better then there predecessors, but i also believe that reviews (not for me) marketing, and advertisement play the biggest role and the Halo train has already started so it's easy to see why Halo would do so well. 

Well, I have been trying to be good, making good posts and not cause too much trouble!

There are so many different facets to a large release and whatever systems actually do get moved as a result of a big game release. However the most important is expanding the market for the console beyond its present userbase restrictions. There are always lapsed gamers for any system who may end up rebuying it for a big release and there are always people on the periphery to current owners who are already tempted to buy a console but haven't yet been pushed over the edge.

The best market and most worthwhile expansion worthy of the name system seller is to areas of the market which are outside the typical userbase already on the console. GT5 fits this bill far better than Halo: Reach so the quality of the systems it sells is of far more importance to the long term success of the PS3 than Halo: Reach is to the Xbox 360. So whilst Halo: Reach will probably accelerate sales through the Xbox 360 owners social networks, the release of GT5 will allow the PS3 to sell to entirely new people altogether and thus will always be the bigger system seller of the two as the majority of systems sold by Reach have already been pre-sold to the market, Reach just seals the deal.

P.S. Probably the most important system seller for the Xbox 360 this year is ESPN, for the reasons listed above.