I'll throw some quick guesses I suppose. Tough when we have so little info to go by, but here goes:
Wii - 21.5mil
No doubt the Wii had its best December this year, but it had a horrific Q2-Q3. From the beginning of April to the end of September, it sold only slightly more than 5mil, or ~210k/wk (in 2008 it did over 9mil). I expect the Wii to be nearly flat in Q1, but up significantly Q2-Q3 on the strength of 09's evergreens, $200 price point, and 2010's new releases. It'll be down in Q4, but with help from Wii Vitality / Zelda, it will manage to maintain its sales lead YoY.
X360 - 10.5mil
The 360 will perform worse than its 2009 during most of the year, but will shine in the final quarter (similar to 2008). With Natal, a potential price cut, and Halo Reach, its Q4 will be monstrous, over 5 million total. It will finish the year in a stronger position than the PS3 for early 2011, slowly reclaiming the ground it lost in early 2010.
PS3 - 11.5mil
The PS3 will have a very strong lead early next year, on the strength of the recent "Slim," $100 price cut, and the releases of GT5 / God of War 3. All of this combined may cut the 360 lead down to as little as 3mil, as it'll be up YoY as high as 30% until September. From late Q3 on, the PS3 will start to see major YoY losses, particularly in Americas/Japan, due to lack of a price cut and stronger 360 sales.
