sell your 70-300mm to me and get a teleconverter for your 70-200 2.8. Or sell them both and get the II version of the 70-200mm (and a teleconverter). It seems redundant to have more than one telephoto zoom.
If you have a 5d3 then your high iso is good enough that the extra stop isn't going to be a big revelation. Besides, you can get some sort of 50mm 1.4 AND the 24-105 for the same price as a 24-70. I don't own a 24-70 but I can say that aside from primes, I cannot bring myself to buy a lens that doesn't have IS, which is another factor.
Canon made a great move developing the 7D AF system, not just for the sake of the 7D itself but for lower end bodies years and years down the line. When rebels get to the point where their AF "seems" lacking compared to whatever Nikon is putting into their entry level stuff, just slap the 7D AF in it. Of course the system itself will probably be like 10 years old by that point but will average joe consumer even notice?
I was actually looking at getting a D7000 until bestbuy (of all places) had the 60D with the 18-135 and 55-250 and a lowepro bag and an 8 gb class 10 card for a thousand bucks even so I really only paid about $600 for the body. This was in the middle of 2011 mind you, before 60D prices plummetted. Since then I've sold both lenses but still have the 60D with EF lenses only.
The tidal wave of used 7D bodies hitting the market will obliterate Rebel and 60D sales. I can get a well worn 7D for a hair under $1000 and a barely used one for a little bit more. Hate to think what would happen when that price drops down to compete with new T4i bodies