PS2

DS without a doubt. At the rate it's going, it should easily surpass the PS2.

There's no way the DS won't outsell the PS2. Only delusional Sony fanboys will post "PS2" and leave the thread, to never return again.

The DS is already on its way to outsell the PS2 in 2009, and the DS will keep selling well into 2011. There's just no way DS won't be number one.

As for my predictions:

1: DS (200m-250m)
2: Wii (150m-160m)
3. PS2 (140m-150m)

PS2 and Wii will be hella close, it depends how long Sony will keep the PS2 on life support.

DS
Wii
PS2

I have a strange feeling the Wii will fall short on what the DS will do. However, Wii sales move at a skyrocket's pace and will no doubt pass the PS2. Proof of that will be seen this Christmas.....where the Wii sells just shy of 8 million.

Which period do you define as "Christmas" because over the next 3 months I am predicting 10-11 million to be sold... and taking out October, leaving just November and December (13 weeks) I would still say it will exceed 8 million just.... December alone it has no chance though, Nintendo will not bulk all of the supply into that one month. (It could manage 5+ mill though for December alone)

Wii is outpacing both of them at their current points of life,

So

Wii
DS
PS2