Well I've predicted Wii2 in 2011 since the launch of the first Wii. Fact is Nintendo revealed early on that they had an HD console in the works (E3 2006). Will Microsoft and Sony actually hold off and will Nintendo start a new generation? No Sony and Microsoft aren't stupid and they both have platforms ready right now with Microsoft's next one all ready getting games (Job postings on Gamasutra last year indicate Microsoft has begun developing games for the next X-Box).
So given statements by Nintendo and Microsoft their next consoles are already in the final stages of development and rest assured they are just waiting for the right time to pull the trigger on the current generation. I think Microsoft might reveal their next console on monday with the console slated for a 2011 release, or they may wait to see how Natal performs this year and reveal their next console X11 or E3 2011 with a Christmas release. Sony has yet to let anything slip about their next console oh wait the teaser trailers for PS4 show that they are at least beginning to ponder the next console.
I think Microsoft will kick start the next generation next year. I expect the 360 to start loosing more market share to PS3 this next fiscal year. I also expect Nintendo to also continue loosing some market share. Sony is the only company without much to gain by launching the next generation. But when Microsoft looses more market share they will be hard pressed and will likely reveal their next platform.
I don't expect Wii2 at this E3, I'd say next E3. I expect NextBox next E3 possibly a teaser at this E3. PS4 I expect in 2012!
Heck I should be an analyst lol