To FF or not?
FF all the way. APS-C always left me wanting more in terms of DOF control and noise at high ISO. The small things are like icing on the cake (larger penta-prisms, no guessing focal lengths, etc). However, there is one aspect of APSC that can never be replaced by FF and that is the fact that if you shoot wildlife, you will get longer focal lengths from your telephoto lenses. Even the 70-200 becomes 140-300, the 100-300 becomes 150-450. You just cant get that kind of reach on FF without paying double or triple the price for that focal length equivalent zoom (not to mention the fact that you will pay more for an FF body).