Min:
360 - 35 million
PS3 - 25 million
Wii - 50 million

Xbox360

min: 35 Mio
estimation: 60 Mio
max: 110 Mio

Wii

min: 45 Mio
estimation: 80 Mio
max: 140 Mio

PS3

min: 25 Mio
estimation: 45 Mio
max: 120 Mio

as you can see, the PS3 is very difficult to estimate...

min.
wii 50million
ps3 40million
xbox 25million

the 360 is non existent in japan and ps3 rocks harder than 360 in europe ,the only place where 360 has a solid base is the US

ps3 - 70M, although selling poorly now, when the price drops and the games start coming out sales will really pick up.

360 - 30M, the xbox breand is mre reconizable now than it was for the original xbox so i expect it to sell more but microsoft havent really tried to expand their market so i dont expect it to sell much more than the original.

Wii - 40M, although i expect it to sell well over this there is a small chance it is a fad (dont shoot me Wii fanboys). i got one on release day and have lost interest in the motion controls.

Worst case predictions:

Xbox 360: 25m - X360 starts tracking more like the Xbox in US/Eur, and ends up slightly ahead in Japan.

PS3: 20m - Tracks similar to what it is now, and no real major defining bump once all games come out. Ends up at GC-esque levels despite FFXIII, MGS, GT, ect. Sony bails in 2009 for a cheaper console and pulls the PS3 plug (skynet fights back), while PSP sales still drive some remote profit.

Wii: 25m - Christmas 2007 ends up being a deathblow to Nintendo, as HDTV penetration is through the roof, MS and Sony drop major price bombs and consumers in the US and Europe start trending more like last gen, leaving the Wii at GC-like levels. Japan remains OK, but still trends better than USA and Europe. Nintendo pulls the plug, and releases Wii 2 in 2009 with a much superior hardware system, and tries to renew a fight vs. MS and Sony.

Isn't the 360 outselling the PS3 in Europe as a whole and has a larger installed base there?

only thanks to the UK which is the same as US but 30miles from mainland europe 

According to the front page of this:

http://www.vgchartz.com/

The 360 has currently sold 3.21 million to PAL territories, while the PS3 has sold approximately 1 million.

According to this:

http://www.vgchartz.com/hwcomps.php?cons1=Wii&reg1=Total+Other&cons2=PS3&reg2=Total+Other&cons3=X360&reg3=Total+Other&weekly=1 

The 360 is currently outselling the PS3 in PAL territories (although not by much). So you are correct on both counts.

Uh, ok. The PS3 is still getting outsold by the 360 in Europe. 

Worst case scenario:
PS3: 3.42 mil
Wii: 8.17 mil
360: 10.00 mil

Assuming today is the Apocalypse...that certainly would be the worst case scenario for all 3 consoles...