I was basically in your situation, except with a 60D (i've got a 10-22 as well as a 70-200 f/4 IS).
I was thinking of getting a 17-55 IS, and I was pleased with the results using it on a 60D for a day. But then I actually bought the 24-70 II (without even testing it) and I'm not regretting it. But then again, I am planning to upgrade to full frame in the early quarter of next year.
Even on a crop sensor camera, this lens still has so much potential. It's just full frame can bring out all it's potential.
Plus, with your 7D (if you're keeping it for a while), you've got a good coverage of focal lengths- 10-22 + 24-70.