You want my thoughts on this? Sony and Microsoft are fucked. Microsoft wants to continue supporting the 360 with Kinect games and connectivity with other products (such as the recently released Smartglass tablet), while Sony is suffering huge losses with the Vita bombing last year. Meanwhile, Nintendo has a huge advantage by releasing the Wii U in late 2012, while Sony and Microsoft's systems likely won't arrive until late 2014 at the earliest.
But by then, the Wii U will have sold truckloads and garnered a great library of games. And since Microsoft and Sony are focused on delivering power, the systems would probably be at least $400. It'd take years before they find their places in the 8th gen, assuming they even do with Nintendo dominating both casual and hardcore markets.
Maybe I'm just a huge Nintendo fanboy, but I don't hate Sony and Microsoft necessarily. I just think the decisions they've made this gen trying to keep the current systems alive are going to screw them over next gen. That's just my two cents on what I think might happen.