Hmm... to me it seems that Bioshock got WAY more hype than MP3. For example, gamespot as a whole IS a Bioshock advert right now. And in the U.S., there's 2.5 million more 360's than Wii's. And Bioshock is the perfect game for the 360 core audience, while a big share of Wii gamers won't be interested in shooters.

So I say:
400.000 Bioshock
200.000 Metroid

On Gamespot yes, Bioshock is more hyped, but it's not the same thing in store. There is one little standee of Bioshock for every posters, big standees, contest and DVD sleeves for Metroid.

Gamespot hyped Bioshock with promotional add when the game launch. There was not alot of hype for this game outside people who were waiting for it. The hype started when the demo was released.

And Bioshock can be a perfect for the core audience on 360, just like Metroid is the perfect game for core audience on the Wii.

380K for Bioshock first week
430K for Metroid Prime 3: Corruption first week.

I agree with your numbers.  Going to say those are mine as well.

Bioshock: 350.000

Corruption: 400.000 

Lets see now...

I will just draw a line in the sand.
No less than 300k for each.
No more than 500k for each.

Bioshock = 672, 323
Metroid Prime = 452,323

BioShock is easily bettering Forza which had 208K in its first week and Crackdown which had 335K in its first week. BioShock is still holding number 1 on sales sites through north america even though its been out for a week.

Metroid Prime will get strong sales. And possibly push the Wii up in sales more.

Lowdown: Both games are strong sellers and will boost their consoles.

Bioshock, though great reviews and a great game, is not an established IP like Metroid Prime, Metroid Prime is an established IP WITH great reviews as well. Definatley Metroid Prime 3.

Bioshock 210K (the most will buy it on PC).

MP3 200K

 So tell me why did GEOW sold so much when it is not an established IP?