Wii Fit includes both the balance board and the game for ~100. Even if the arcade drops to 150, adding in a harddrive brings it back up to ~250, then even if you figure in Natal bundled in at ~50, that brings an entry price of 300. That's possible, though a somewhat optimistic perception. This will not even include any software; in comparison, the Wii launched at 250 including a game.

As far as those that are interested in motion control, the majority will already have a Wii. Is 300 low enough for them to consider a second console? Will the previous 360 owners want to purchase Natal at full price when it will only get up to full speed toward the end of the 360's lifespan (the 360 will be five years old at this point; assuming it makes ten years, that is only five years of support for Natal)?

I'm not doubting that Natal will meet with fair success (20 - 25 mil units lifetime, including bundles), but to turn the tide of this generation in any manner is debatable.

If by turn the tide, you mean catch Wii...I'd say that it is almost impossible. 

^ By turn the tide I mean demolishing the ps3 or at least closing the gap to the Wii. I can see it temporarily stalling the ps3, however, I think the ps3 will still continue to catch it gradually, eventually ending in equal install bases toward the conclusion of this gen.

That is significant, but hardly the major impact others seem to be anticipating, considering it will merely help to maintain it's lead.

If it's more than $100 then the thing simply ain't gonna sell, because consumers are getting tired of buying expensive hardware accessories just to play certain games *cough* GH/RB, Tony Hawk Ride *cough*

200 if they want profit, 100 if they want success.

Ha, if the wireless adapter goes for $100, and a 120GB HDD goes for $150.....

Natal $599.99 "Work more hours"

$100 will most likely be the price.

Well...Natal isn't going demolish the PS3, and I do think it could made some gains on Wii in NA, but certianly not catch it...even in NA.  Slim is helping PS3 move against Wii in Japan, but I doubt it's going to catch it...same thing for 360 Natal in NA. 

Whereas your analogy may be true to accessories I actually think they regard NATAL as more than an accessory so this will not apply. They want this to be adopted as close to a standard as possible so they need as many old 360 users on board as they can.

They will price this more than the lowest rumoured price and a lot less than the high prices quoted. Still I think it will come in the $80-100 bracket myself.

Those guys are considered fanboys by most.  So no matter what you tell them, show them, prove to them, they will always think its an inferior product.

Most consumers will go with whats popular or well marketed.  And I will guarantee you Microsoft will market this thing as well if not better than they did Halo 3 (its marketing campaign was legendary).

OT:  

Hopefully they can keep Natal down below $99, but unfortunately I am not counting on this.  I never thought they would charge full price for ODST either and they did.  The main difference here is that I think Microsoft has decided their success from here on out is in the hands of Natal.  Hit or miss they will be stuck with it for the remainder of this generation and I don't see them trying to get greedy with it.  $99 for the Natal and a Wii Sports nock off would sound fair and should sale really well.