Halo also had the entire 13-16 year old crowd thinking it is the greatest game that was ever created. We all know how much pressure a 13-16 kid can put on their parents to buy it for them.
(sorry had to take a shot at the ultra overrated Halo series)

I think GT5 will do outstandingly well since it has been a long time since a great GT game came out. Think about how many people purchased GT5P when it was only an over glorified demo.
I think GT5 will easily double and then some the sales of GT5P.

Seriously, it never ceases to amaze me how many people underestimate Gran Turismo's selling power.

What do you think is the reason and god knows intelligence is not one of them.

I think big series are always open to generational shift playing with sales, the "first next gen" rlease almost always does a little better (though GT5P may work against GT5's favor in this regard then).  GT2's actually the worst selling "main" game in the series though, it hasn't been continual rise since GT1 (which is different from Halo 1 -> 2 -> 3).

The MGS comparison doesn't exactly bode well for GT though, MGS4 barely outsold MGS3 and didn't come close to MGS2.  Using the same logic, wouldn't it be fair to say the same will hold true true for GT5?  

1. Look at GT4P's sales compared to 4.

2. MGS isn't as big as Gran Turismo. You're not taking the scale into account.

Edit: Oh, and I forgot that GT2 sold less. It helps my point that it could be a fluctuation then. :)

Guessing 8m+ for GT5 and saying it won't outsell GT3 is underestimating GT's selling power?  lol, I think you need a little more perspective if you really feel that's the case...

How well did you expect GT PSP to sell btw?

You were saying Halo is on the rise and GT is going down.

As for PSP sales, I wasn't expecting much. It's in line with expectations.

I don't think it'll be a close race at all. PS3 is already crushing 360 even in its own territory (NA) right now. And that's before FF13 releases in Japan as PS3 exclusive, then GT5 worldwide, plus God of War 3. It looks more like a landslide to me than a close race.

MS has basically no answer to those juggernauts... It's pretty funny to see people always talking about NatEyeToy as MS main hope. It's a gimmick aimed at catching some of the Wii crowd, nothing more. If Eyetoy didn't succeed, there's around zero chance Natal sells millions. The casual crowd already has Wii collecting dust now, I highly doubt they'll rush to buy NatEyeToy.

1. Trying to extrapolate GT5P/GT5 from GT4P/GT4 is inherently unfeasible for a litany of reasons.  Do I really need to go into it?

2. Bigger series tend to get more effected by userbase fluctuations, it's smaller series that tend to hold up better.  Again, look at Nintendo and how Mario Kart evolved sales wise from N64 to GC to Wii.  This works more in MGS' favor than GT's.

1. You said GT5P works against GT5's sales.

2. I don't see your point here. At all.