Bioshock and Metroid, are going to be quality wise probably in the same level. maybe with a little advantage to MP3 for controls.
Sales-wise, Metroid should easily beat it, just because it is Wii`s top shooter, thing that Bioshock isn`t. Online is really important for 360 titles in order to sell great. The only exception is Oblivion, but that game is from a genre which has very few alternatives in 360.

So:

1st week - 250k
1st month - 550k
End of year - 1.1m

A lot of people who don't know what Metroid is are going to buy it because it's an FPS, and has a lot of hype built up around it. So it should sell better than Prime or Echoes.

Remember, the Wii has a lot of new customers who didn't own a Gamecube.  Red Steel sold well even though it was rather poor as a game.  Metroid is going to be awesome, and sell to a larger userbase than Red Steel.  It should do very well. 

Sadly they're going to be exploring around, and say it sucks as an FPS...

Thankfully I think Nintendo realizes that is the gamer in the family that gets the rest of them to play Mario Party and Brain Age.

EDIT: First week 270k, Sept 30 750k

EDIT2: Oh and Bishock will probably be a better game, but people LOVE sequels, especially ones that claim to improve a franchise.  I also think Bioshock is a little too high-brow/sophisticated and advertised too little for mega success.  The hype has the hard core excited for it, but the mainstream seems to want sequels and casual games right now (Guitar Hero III is going to be huge)

300k+ in the first week and 1million+ worldwide by the end of the year easy.

Can I get a side of Contempt with that Vindictive Jealousy?

1st week: 169K

rest i wouldn't have a clue. If the game prooves to be the best controls for a fps shooter style game on a home console they could sky rocket by end of the year. This will happen by word of mouth if its good.

Bioshock and Metroid 3 are both awesome games but, I think that Metroid will outsell Bioshock just for the fact that people can get it on PC and, let's be honest if a game is on PC... a LOT of people will sadly not "pay" for it.

In terms of games, I think that, for what I've seen they are really good and quite different so, get both!!

220k first week
1.2mil by 08

I reckon there will be a vast number of more sales for the MP3:C than the past two installments, because there are people like me who haven't bought either of them but are going to buy the third without a doubt in my mind (it is among only 2 other games that I will get without a doubt in my mind - Super Paper Mario and Galaxy)

Metroid 3 - It's set to be the Biggest FP game for the Wii, and if it is as good as the previews say it will have a great start and good legs while the Wii market expands. I expect a big boost in Dec.

First Week - 300K
First Month - 800K
End of year - 1.3 million

WW it might out sell Madden. (on current gen platforms)