Believe or not Nesgran and Spanghew the 70-200 2.8 will give you some surprising results on a crop sensor, I would suggest renting or borrowing one to give it a try. The 85 is really nice though, IMO it is one of the best primes that Canon makes.
I have a Canon 70-200 f/2.8 and it works very well on my 7D and my old trusty rebel T3i. Though many people think it magnifies the focal length, it does not, it “appears” that way due to the 1.6 crop but no actual zoom factor is taking place. If anything, your getting the crisper cleaner image in the center with a crop sensor camera.