I am hard-line proponent of core stability stuff like step-ups, the plank, unsupported rows, etc. I think one of the best chest exercises I ever learned was the medicine ball pushup, those things are killer.
The following is a link to help people with AC joint issues in their shoulder, in it they teach a bunch of different push up variations:
URL
The key here is to remember that core training should be an
element of your routine, not a focus (provided you ultimate goal is to be a mountain of meat.
Core stability exercises will never depose the undeniable benefit of the big three: squat, deadlift, press.
I guess rows too.