It doesnt take a crystal ball to know that SONY, MICROSOFT & NINTY R&D department will be working on future console projects, it takes years to develope a console so its best to get started early.
the whole talk about the PS3 lasting 10 years (before they release a new console) will only happen if its financialy beneficial to sony, not becose the PS3 is so powerfull it can last that long, future (5+ years time) technology will make the 360+ps3 look oldhat, its wether it makes sense to release a new console by then.
for console makers it makes sense to wait aslong as possible before releaseing a new console, since its fair to presume micrcosoft will be developeing a new console sony know they must develope one to keep up (or vice versa if you prefer), asfor ninty they are harder to judge, the market they aimed the wii at doesnt "need" constant (5 years) tech updates but i think they will still be developeing a new console, when it will be released well that another matter.
and thats what it comes down to realy, are they researching new consoles? yes. when will they decide to release new consoles? know one knows at moment, we can only guess, but the smart money is on 2011 (due to the usual 5+ years cycle).
lets wait & see, and while we are waiting lets enjoy playing games (regardless of what platform its on)