Upgrade to 6D from 7D ?

I would say get the 6D and the 24-105. Definitely keep the 70-200 IS II.  Also, if you're so into low light grab some cheapo primes. 50 1.8, 35 2, 28 1.8 (not as cheap).  If you buy nothing else at least grab yourself a 50 1.8. You will simply love it on a full frame camera.

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