Here are my predictions for 2008:
Wii: More of the same. Only that it'll sell 3-4 million units more.
360: It WILL sell more than this year. It will sell 1-2 million units more because of price cut (Pro: $320, Aracade: $270, Elite: $375) and GTA IV. It will improve in the 'others' region, but get outsold by PS3 constantly.
PS3: It will sell 1 million units more and 'others' region will be its biggest gain. And there will be no price cut.
End of 2008 predcition:
Wii: 34 million
360: 23-26.5 million
PS3: 15-18 million