http://kotaku.com/gaming/bah-humbug/nintendos-reggie-totally-mehs-halo-3-sales-305312.php 

"Will they sell a lot of software? Certainly. Will it sell hardware? I think it's an open question... I think that the Halo 3 consumer already has the hardware, because they're playing BioShock and Crackdown and a variety of games that are, in the end, quite similar: first-person shooter experience, multiplayer capable online. Tell me what's new?"

It's not as bad as the title makes it out to be. He just thinks that Halo 3 won't sell a lot of hardware which it more than likely won't. Don't get me wrong, there will be an increase this week and probably the next, but not enough to make a big deal out of it.

It won't move hardware like Smash Bros or Wii Fit (especially the latter), but it will move lots.

 I agree with what that man .. points at twesterm .. just said

I think the "Halo fans already have a 360" argument is bunk. Do a lot of them already have the 360, yes, but I'm sure there are just as many out there who were waiting to buy a 360, and Halo tipped the scales for them. Plus, the Halo-edition 360 should drive additional hardware sales. I expect to see a sizeable bump in NA hardware sales.

 I totally agree; I predict * looks into his crystal ball * 150k+

I'm sure there will be a pretty large bump. How large? Well I really have no clue. Off the top of my head I would say 360 sales should be around up by around 250K for the week. I'd say they'll be back down by another 100K next week and then almost normal after that though. Whatever hardware sales boost it gives will be very top-heavy.

 I'm somewhere in between.

On one hand, as you say, it's absurd to suggest that a healthy portion (whatever that means -- 50? 60?) of Halo fans already owned a 360 before this. Not only are there other big budget titles in the genre on the system, but pretty much everyone who buys in to the Xbox brand is aware that Halo is the killer app. It's not like Sony last generation, who could stand on the twin giants of GTA and Gran Turismo (although that's obviously hobbled now). Xbox is nigh-synonymous with the Halo name.

On the other hand, I absolutely agree that another healthy portion will be buying an Xbox because of Halo 3. 

In other words, I think the actual answer is: "Halo will move some consoles, but perhaps not as many as a game of that magnitude might suggest," which is 1) vague and 2) not very satisfying, because people like definitive answers and not a shade of grey. 

I don't expect a large bump for the 360. And "The wisdom of the crowd" seems also not to think that there will be a really large bump, they expecting a really small one. Look at my footer :o)

Halo2 sold almost as much as 360s entire NA user base, plenty more will buy a 360 for Halo but that does not mean they have to buy it right away.