I go with you.

Not because I think it will sell so poor but because everyone is giving it high numbers again like
Some already did with SMG.

80K first day  100k first week. 

400K First day

700K First week

Come on guys JAP has now proved that it is THE casual market..

Well after what happened to SMG, that's hard to predict...
I think, according to recent game sales, that Wii owners are not people buying games on first day or first week. That would be especially true for a pure casual game like Wii Fit. After all, remember the first weeks of brain training 1&2, english training, nintendogs...
The game releasing december 1st, It will probably benefit a little from christmas boost, though I expect it to sell more the following weeks when it's actually christmas.
With that in mind, my guess is :
First Day : 75K
First Week : 160K
Hardware Boost over previous week : +40K

After SMG my expectations are much lowered. It seems like you have to be portable to win there.

80k first day
200k first week

Past predictions have proven that I have no clue about the purchasing habits of Japanese game buyers.

That being said, I would predict with 100% certainty that first day sales will be 138,673.

Gamerace recently sent me a private message asking that in light of the recent performance of Super Mario Galaxy in Japan have I changed my stance.

My short reply to Gamerace was...

No.

John Lucas

I think it will beat SMG but just barely.

I am not going to be proud of my system if Super Mario Galaxy gets beaten by WiiFit.

I'm going to go out on a limb and predict that Wii Fit will have lower than expected week 1 sales, will follow a pattern close to Brain Training and have very steady sales for a long period of time which result in very high total sales.

I'm going to out on a limb and say that WiiFit will fail horribly because Brain Training was $30 and portable.

Just a thought...