Wii will not expand the industry that much.
Wii:90-120million If it keeps selling like it is.
PS3:75-100milion Some really great games coming up.
X360:35-50million Got nothin' after the end of 07.

If the Wii goes the way of the Gamecube and suddenly stops selling(highly unlikely).
PS3:90-100million
Wii:60-90million
X360:35-50million

With the XBox 360 selling at roughly the rate of the XBox, and the PS3 selling below the rate of the Gamecube I expect that they will both end up at (roughly) 25 to 30 Million ... This leaves most of the rest of the market to the Wii which could hit 100 to 150 Million.

Even with massive growth in the industry (and in multi-console owners in particular) I couldn't see the PS3 or XBox 360 breaking 40 Million.

 360 and PS3 numbers very low there VERY LOW!

 I think they're low too, but there's some history behind it - every generation since the NES has seen a single leader take up the lions share of the market. The SNES ended up with only about 55%, if I remember correctly, which was the lowest for the last four generational leaders. 

Wii - 9.5mil - 6 billion
PS3 - 20m - 20,000,001
Xbox360 - 20,000,0001 - 20,000,001.5

@RolStoppable, your numbers are insane, if you truly think that the wii is going to sell that well and the other systems that bad you must be taking lots of drugs.

6BILLION(lol) THATS WAY TO HIGH and 20million is too low.

I think my Wii numbers are accurate and it will be somewhere between the 2 figures.

The Wii numbers are accurate but selling to most people in the world when most dnt have enough money to buy 1 is insane.

In order to compare the sames from last gen, we need to take into account the fact that alot of households went though more than one PS2, almost everyone i know with one is on atleast their second. This isnt a complaint, lasers dont last forever.

If the wii can manage to do the same and still be so attractive that after 4 - 6 years the consumer is happy to replace the system when its worn out, then the wii will easily match the PS2s sales.

I think a big factor in the wii strategy is the fact that they are targetting not only a wider audience but also pinpointing key areas with things such as the wii balance board, this could end up with the household needing 2 or maybe more Wiis, which ofcourse will be terrific for nintendo. If this happens i can see the wii easily topping 150million. Its worth noting that the wii is gaining alot of popularity in korea, to my (admitedly limited) knowledge no japanese console has ever sold there, and considering the purely untapped market that it could penetrate there, this could give them another 15 - 20% more sales.

As for the other 2, i can see the 360 generally selling ok for the next few years before it is either killed by MS themselves with a new machine or they just "do a sega" :)

The PS3 will do well, but it will never be what the PS2 was, they have already lost the mass market to nintendo, but i can still see them shifting 70 million over the long lifetime it will have. Im sure it will sell atleast 20 million as a BD player alone.