I was having a thunk about this today. I think we might see more dedicated custom hardware in the NextBox™.
The PS3 is very versatile with it's seven cores, but another approach is to use dedicated custom hardware like a GPU (already widely used) and PhyX physics processing units (PPU). This enables a system to be very efficient at specific tasks (ie 3d gaming) without needing huge CPU grunt, therefore keeping the price down.
The old Amiga with a weedy 12Mhz CPU used to stomp all over 60Mhz PCs of the day because it had dedicated hardware for blitting, memory transfer, sound, etc. Of course, when the 3D revolution came, the Amiga's 2D hardware couldn't cope and the rest is history.
Maybe a NextBox™ with a dedicated PPU,
ToE (Network processor) and other bits would be a possibility?
The only problem with this approach is if something new and huge in gaming comes along in the console's lifetime that it's not designed to handle, it is dead in the water.
I rambled a bit there, but you get the idea.