What is the lowest realistic expectation for lifetime sales of Wii,PS3,360?

[spartan117]

My new expectations:

Xbox360: 25M (if the taliban destroy bungie)
Wii: 25M (if Mario dies in the next game^^ and the sales drop in 2008)
PS3: 15M (if BD lose the war and PS3 lose exclusives like FF13 and MGS4)