Well, we can all agree that FF XIII is out of the race, even with 360 and PS3 added together.

We can also all agree that GT 5 will beat Halo Reach in Europe and Japan and Halo will win in the USA.

The thing is, the best selling PS3 game, by the time GT 5 comes out, will be MW 2 with probably about 7m, and GT 5 needs to sell an extra 3m, as Reach will certainly be around 10m, which seems slightly unlike to me

So overall, I am going to have to go with Reach

you just dont see that in europe, racing is still important and people are just holding back to buy GT5 ...

all will depend on Natal, price cut and FPS competition (CoD)

http://vgchartz.com/worldtotals.php?name=gran+turismo&console=&publisher=&genre=&minSales=0&results=50&sort=Total 

http://vgchartz.com/worldtotals.php?name=halo&console=&publisher=&genre=&minSales=0&results=50&sort=Total 

In case anyone is wondering about the strength of the GT franchise, here are the shipment amounts, straight from Polyphony as of September 2009:

Worldwide

I don't think GT5 will sell as much as the previous games because of the install base of the Ps3. I'd say it could reach 8 million at most at this point. We will have to wait and see how Sony will advertise this behemoth of a series :D

Oh I like the way you think!!!

Gran Turismo 5: 10.5 million

Halo Reach: 9.5 million

FFXIII: 6.5 million. 5 million on PS3 and 1.5 million on 360.

Halo:Reach.

All signs point to GT5 continuing the reduction of sales that started with GT4.

Why?

First - Increased competition. GT used to be the only game in town for truly realistic looking cars. Now nearly every racer looks photo realistic and since Forza 1 the GT series has had a superior alternative for the racing sim. Will GT5 surpass Forza 3? Maybe. To an extent that the more casual race fans choose to purchase a PS3 just to play it, doubtful.

Second - PS3 just doesnt demand the marketshare that the PS2 had and the fanatical GT fan already purchase a PS3 for GT5:Prologue.

Third - The PS2 was still waiting its first AAA blockbuster release when GT3 hit the ground. That is far from the case with the PS3 and GT5.

@ thx, so you think it will continue the decline that GT 4 started (though its total sales are still above Halo 3 btw). In the same way that GT 2 started a decline? What about the decline from Halo 3 to ODST?

It's pretty darn obvious that Halo: Reach will sell the most with GT5 being second and FFXIII FAR away in third place. GT PSP was rubbish however I doubt that game has damaged the GT brand too much however from what we know GT5 is an absolute beast of a game. Purty game, 900 cars, weather and night racing, blah blah blah along with it being from an already big franchise ensures it will be the best selling PS3 title released on the console.

The amount of cross promotion which PD will be able to do with GT5 is amazing though, they hold so many of the licenses besides that of F1. Nascar, WRC, Super GT, IRC and hopefully a decent online will ensure this game has very good legs. Gran Turismo on the box sure won't hurt it either. :P