This is an interesting question and a lot will depend on Kinect I think. Normally the expectation would be for the effect to dampen post release, and of course in 2011 the 360s isn't the new SKU driving a spike but the standard model.
I'm thinking it'll be close but I think full 2011 sales Wii might still pip 360 at the post. My main reasoning is that I believe the 360s saw a big percentage of existing 360 owners in US trading in their consoles for the undeniably superior 360s SKU. Probably 80% of the people I personally know in US with old 360 models traded them in. I know, annecdotal, and I normally wouldn't mention it, but across multiple forums, etc. the feeling I got was the 360s drove a big spike of double dipping that I can't see repeating for any reason in 2011.
Now, without this uplift I don't think Kinect - while I think it will remain successful - can cover the additional sales driven in 2010 via the new model to put 360 ahead.
But, it might, because I think it is going to be close. And of course if Wii downtrends a bit more in 2011 then 360 might take the lead that way.
Try to be reasonable... its easier than you think...
