Doubtful. There will very likely be another Halo in 2012 from 343 on X360. Therefore the earliest you would see a new 360 would be fall 2013.
Gears 3 is now fall 011 so there will be no new Xbox in 011 for sure. Now you just need a fall 012 title. That is most likely a Halo, since MS said they will be coming more often than every three years. Also, there's a poster on GAF who's uncle works for 343, and he said the next Halo will be on 360.
Also, quite frankly it seems to me the market is becoming more and more third party oriented. Just because there's fewer first party exclusives, doesn't mean there's not lots of big games coming all the time. Coming soon Enslaved, Vanquish and many others for example. And I wasn't too pissed about Gears 3 moving (though I was pissed) because Crysis 2 and Bulletstorm are coming next spring. Possibly Deus Ex Human Revolution too. So it's not like I wont have shooters to play.
Microsoft's big push right now is Kinect. They are probably backing off the hardcore a bit.
