Optimistic view: 80 million ltd sales. 100 million could be remotely possible. PS3 must last for 10 years to reach 100 million sales.
Pessimistic view: 65 million ltd sales. PS3 will slow down in sales. PS3 sales peaked in 2009.
My view: Some where between 70 million and 80 million ltd sales for the PS3.
Chances are slim of their being 2 consoles selling over 100 million ltd sales in the same generation. DS is a hand held and is not in direct competition to the console systems.