2010 - 2011 will see new portables from Sony and Nintendo I imagine.

I think it's too early to predict the home consoles lives but I can see PS3 Slim and Motion controller along with the X360 and Natal packages next year push those systems for a year or two at above a $200 price point which essentially means they have a long life left in them.

Wii will continue to sell and after nearly 3 years and still not one price cut.. I think it'll be at least another 3 before we see a successor.

Microsoft will put out a console in 2011 to get a jump on the competiton like they always do.

Nintendo will release a console in 2012.

Sony will release a console in 2016 (something about the 10 year plan).

What are handhelds?

Sure there is. Console add-ons never have the impact that they could have as a whole new console. That's why Wii succeeded, whereas the Wii remote would have been on a "Nintendo's greatest mistakes" list if they had pushed it out as a GameCube add-on as originally planned. Natal will be like the original Xbox: an expensive, massive beta for something better coming down the pipe. Microsoft will learn the pluses and minuses of Natal, and then quickly segue that into a new console.

I don't think the PS3mote is even intended for this generation, to be honest. The feature will be pushed back, and then you'll see it launch their next console with a bang.

Again: 2011 (Nintendo and Microsoft) and 2012 (Sony). Nintendo said they would replace the console when they can't make more software for the Wii, and i seriously doubt their ability to stretch the Wii out any longer than their previous consoles from an internal software perspective, aside from the fact that Japan is clearly not going to adapt the Wii in the long-term like the West has. The only advantage the Wii will have is that, unlike other Nintendo consoles since the NES, Nintendo will be able to keep selling it after the new console launches.

Microsoft is going to want to build a Natal-focused console if they're serious about Motion controllers, as that will be the only way to effectively fight Nintendo. Equally, Microsoft is going to want to re-synch their console strategy with PCs. I mean, 360 is based off Direct X 9, right? Direct X 11 is coming soon, and Windows 7. Microsoft is going to want a console more in line with their advancing PC interests.

Sony will want to hold on to this generation longer, if only to optimize profits from PS3. But they'll see the writing on the wall of new consoles from both Nintendo and Microsoft, and they'll have to move, just a bit later.

Always do?
This gen is the first time they did that as the original Xbox was the 3rd released console last gen.

They have yet to make it a trend.

I think all 3 are selling too well and with the HD twins especially still have too much under the bonnet for a new gen to start in the next 2 years.

I think an announcement as to next consoles in 2012 at the earliest.
I don't see them announcing consoles with too big a wait next time as they don't want anyone to get their typical apparently early lead on the market without competition or use specs to confuse the competition again.

2012

2013/14

2010/11 for handhelds

2012 with the Wagglebox. Then the Wagglestation and shortly after the Super Wii.

2012. I'd prefer it to be 2014-15 though.

If that happens, and all 3 concentrate on motion control, they're all fucked, including Nintendo.