5-6 years apart

it's because the development it's taking longer, and didn't start show live til now.
2008 upward.

many developers will release all they can to recoup cost on the engines.

even if the next gen console start i can see people making games for this gen consoles.

firmware updates and such. A PS4 won't be necessary for AT LEAST 10 years. Neither will a new Xbox.

I strongly believe Nintendo will be the first one into next gen with basically a Wii HD, but with a new name of course rather than just Wii HD. It will likely be 1080p, a little more powerful and focus on motion controls.

Because Sony & Microsoft lost a crap load of money this gen, they need to make some of that back. And why in the world would Nintendo push for a new console when Wii is selling like hot cakes.

Nobody has an incentive to come out with a new console, therefore Nintendo's & Microsoft's consoles will last longer this gen than last. I'm guessing total will be around 10 yrs for all three.

This generation is most likely to win in two years.

Microsoft and Sony jumped the gun by going as advanced as they went, and the industry(minus Nintendo and some select third parties) decided to follow them. One economic downfall later, it's obvious that HD came way too soon, so it's basically going to have to ride out now. I don't think Microsoft or Sony could afford to make another graphical leap the way they made this gen, I don't think most third prties can afford to follow them if they do, and I don't think either has the ingenuity to disrupt or even join the Blue Ocean in the ways that Nintendo did.

Nintendo just doesn't need to do anything but sit back and let this Wii/DS thing ride out.

Cause SONY cant afford to release another console before the PS3's 10 year life cycle :P but i personally think it will not last longer than normal cause M$ is gonna launch a new console in 2011 and SONY will HAVE to follow suit.

This generation of machines are much more future proof than any other consoles before them. I know that people hate that term, but it is true. In every generation before this, the box you brought home day one was the same exact box you have today. Now with all three of these new consoles there is almost no limit to what they can achive through time and OS updates.

Another reason is the extream shock that the switch to this generation has caused for 3rd party developers. Should new consoles come out in the next 2 years, EA, THQ, Activision, and more would all be in dire straights financialy. Moving forward to fast this gen could result in a crash to the market.

One big reason is the new mainstream appeal of gaming. The people buying the Wii today are not the kind of people that want to update all the time. These are the people that complain about needing a new TV every year, and how they don't want a new movie format every 10 years. Convencing them to go and buy a new Wii in a year or two is not very likely.

Last reason is development costs, and time. This generations machines are so much more powerful with parrallel proccessing, and abilities to perform new graphical techniques that engines took much loneger to build. Thanks to all that extra power the amount of time needed to take care of graphics and have a game that does not look unbalanced is much greater. This reason ties directly back into the thrid party devs money issues. Devs need time to take full advantage of these systems, and work out the complications of multi core coding before we move forward.