DS - 134 million (+38 mil)
Wii - 79 million (+33 mil)
PSP - 54 million (+11 mil)
360 - 42.5 million (+15 mil)
PS3 - 31.5 million (+ 12 mil)
Edit - I'll give some reasoning behing these. I've gone and looked at the increase in annual sales for each console but they are a bit all over the place. Nevertheless they are all increasing year on year so far and I expect that to continue next year with no new consoles on the horizon. A PSP2 could throw a spanner in the works, but I don't expect one.
DS - Not only is the DS Lite selling unbelievably well, but the DSi has revived sales in Japan, so I expect it to boost sales worldwide when it gets a release. It's possible that they will hold off on the DSi while the DSLite is selling so well, but as the DSi is not a direct replacement, then I expect to see it by mid 09.
Wii - This figure is based off the 2.8million per month figure that we know Nintendo are producing. This number could end up being much higher, but we also know that they have boosted production to an unknown level for the Xmas period, so we know they can do it. Assuming demand stays the same and we see no sign of it slowing down then 80+mil could be easily reached.
PSP - Seems fairly stable, unless it starts it's decline then another 10-11 mil should be possible.
360 - I think the mass market price point has hit a nerve, the 3 year warranty is giving piece of mind, plus a 360 slim mid year will keep the demand up for the 360. The 360 will sell 12+ million consoles in 2008 and I have budgeted on only a 20% increase for 2009 even though the price cut has given a 50% increase so far from earlier in the year. A slim will only maintain that momentum. I don't think 15 mil is unreasonable.
PS3 - Probably the hardest of the bunch to pick. I'm banking on a price cut, but I think it will only be $50 and not until end of Q3. I've estimated an increase of around 15% on 2008. Even with a cut of $100 I think it will be tough to gain much more traction until GT5 & FF13 are released but they won't be until the end of the year and FF13 will be 2010 outside of Japan plus multi-platform.
Never argue with idiots
They bring you down to their level and then beat you with experience