You know John Carmack. He's the programming wizard responsible for games like Doom. You know what John Carmack thinks?
He thinks that Sony could release a new console before Microsoft. Here's his rationale: "The whole jockeying for who's going to release the first next gen console is very interesting and pretty divorced from the technical side of things," he says. "Whether Sony wants to jump the gun to prevent the same sort of 360 lag from happening to them again seems likely. As developers, we would really like to see this generation stretch as long as possible. We'd like to see it be quite a few more years before the next gen console comes out, but I suspect one will end up shipping something earlier rather than later."
Sony has repeatedly stated that the PS3's lifespan is ten years. The console came out in 2006 in Japan, which means that Sony is not expected to release a new console until 2016 or 2017. With the buzz around Project Natal, Microsoft has recently been talking about a longer shelf life for the Xbox 360.
But, all of this is still unconfirmed and merely speculation on Carmack's part. In the rest of the link below, Carmack offers his opinion about more futurey stuff as well.
Carmack talks next gen consoles... and beyond [Digital Foundry via GamesIndustry]