I'm sorta confused, are you saying that Halo 3 is an annual franchise? O_o Or did you mean Halo is an annual franchise or that sales have peaked for Halo? I would definitely refute the last bit.

It's realy in treyarch-hands now. I think if they're doing vietnam and if they're doing it good, it will sell like crazy cuz vietnam isn't as milked as MW and WWII

there was hype for WaW, but i think by now everyone knows that Treyarch is nothing but disrespect towards IW. so basically, people are going to expect it to be bad and its not going to sell much. and besides MF2 will have way more weeks to sell in 2010 than COD7 so it should outsell it without a problem in 2010.

i bet call of duty 7 will really split the fan base because it will be that much better than mw2

I would bet against you on this one, especially if CoD 7 is released on the Wii, DS, and PS2 again (which I hope it is as the Wii needs good core games with online).

Also, CoD 7 is supposed to be Vietnam based. WaW suffered from the glut of WW2 games on the market. As far as I know, there aren't really any Vietnam games at all on the 7th generation consoles. If they do this game correctly, I think that it will quite refreshing and a nice addition to the FPS genre. I just hope that they make good use of the choppers in this game. It would be really cool if they let us fly the choppers in multiplayer.

No, impossible.

See 2008 for example. World at War destroyed Modern Warfare, even though the latter had huge legs.

See the 360 sales comparison. 

The huge launch of MW2 makes it more frontloaded. I doubt the 360 version can even keep up with its MW1 legs. The PS3 version will sell higher, but this will be countered by a larger userbase buying the next CoD7 (compared to WaW).

Max sales for MW2 for the year: 6 million (X360 MW1 did 3mil)
Min sales for CoD7 for the year: 6.5 million (I don't see it doing less than WaW)