I expect the PS4/Wii U/Xbox^3 to all launch at a $399.99 price tag.
With the Wii U launching in Q4 2012 (estimate), it will naturally have the weakest hardware compared to the PS4 and Xbox^3 launching in Q1/Q2 2014 (estimate).
Additionally, Nintendo will probably sell its hardware at a $50 profit per unit (cost reduced by using slightly less powerful hardware). Sony and Microsoft will probably be willing to take as large as a $50 loss per unit. The $100 margin will allow Sony and Microsoft to use better parts (especially if they are launching 14-18 months later).
Though, I think we are getting to a point where hardware advancements aren't going to make as much of a difference in the final game products as advancements in SDK software will. Maybe we will see some big breakthroughs in SDK R&D from the big 3.
Personally, I feel a bit bearish towards the upcoming 8th gen home consoles' game libraries.
I hope they prove my worries wrong, very very wrong. o.O
