I predict 1-3 million software sales.
300-500K Hardware sales. Ps3 already selling like 200k per week, so minimal grow of 100K (limited edition ps3 already sold out).

I don't know how many times I have to repeat this mantra: hardware sales never spike as much for big game releases as everyone seems to think. Go back and look at the laughably over-estimated predictions on this site for the release of Brawl, Yakuza (in Japan), and Devil May Cry. Remember the Halo effect: even on the week of Halo 3's release last year, 360 hardware was only up by 50% on the week. Metal Gear Solid has considerably less appeal to the non-serious gamer, so expect a lesser boost.

Assuming a worldwide release, I would expect sales to be up about 25% for the week, which would put the PS3 somewhere in the 225k range (assuming 180k normal weekly sales). I honestly don't see any possible way for hardware to reach 300k, which would be a 66% increase; consider that the extreme upper limit.

I am of course prepared to eat crow if for some reason there is a gigantic hardware surge when the game comes out. That seems unlikely though, since the PS3 has never topped 250k in a week outside of the holiday periods and Euro launch. :)

Its gonna sell a lot, my gamestop has had a lot of preorders already. I'd say 700k in its 1st week in America alone.

But you are ignoring the fact that this is the reintroduction of a b/c model, at least in the US.  That in itself should give a nice boost.  I'm not sure if they have confirmed it for Japan and Europe though. 

As it is a WW realease I predict the figures will be for the first full week:
Japan 400
America 550 (Americans aren't "that" interested in it)
Others 600

MGS4 WW: 1.55m

PS3 WW: 350

Hmm, I actually don't expect MGS4 to sell more than 750,000 copies the first week -- the install base will still be relatively small (only 14 million). Diehard fans, such as myself, will snap it up, but the franchise doesn't have the broad appeal of GTA, so I don't expect Halo-sized opening day sales.

That said, I fully expect MGS4 to break all the Metal Gear sales records, and it is indeed going to be a PS3 system-seller. This is a true blockbuster game, with epic characters, open worlds, multiplayer online, and accessible gameplay. Word of mouth buzz will ensure it will have Gekko-style legs. We're talking monster holiday sales, 9 to 10 million in lifetime sales, and a ton of PS3 units moved.