Wii:
I think they should add around somewhere between 24m-32m units. I'll go with 75 million units at the end of the year. This is all depending on if they decrease or increase their production... and if the bubble that seems to be around the Wii burst or if it keeps going through the year.
360:
The Xbox 360 had a very slow start to the year, but the end has been nothing short of spectacular. The recovery they made after dropping almost 1.5 million units behind Sony's PS3 has been a bit shocking to many on here. I think it'll average out around 200k/wk perhaps a bit more... this depends on how many Arcade models Microsoft can get out to the consumers. Taking that into account as base I think they will come very close to 40 million units WW. This of course is based off of sales of just 3.5 million units on the last 10 weeks of the year. I think they'll do 12-13 million units next year if not more. The first half of the year will be very telling to see how the 360's 200 dollar price tag put's it's average at.
PS3:
This is the wild card. I can't even begin to guess what a price drop would do because there are so many ways they can drop the price to try and minimize damage to their bottom line. My best guess would be in the 30 million range depending on how much they reduce the price of the console and the timing and marketing of that price reduction.