You're missing an option.....
Answer: 1 case, because I returned the rest of them.
I had the belkin silicon rubber protective cover, the incase black silicon rubber protective cover, and finally the incase slider.... which is what I am keeping.
In my opinion, incase slider is the best. It fits snug, doesn't allow dust below the case, the screen protector (power support anti-glare) fits perfectly with it, it has a nice texture and provides adequate protection.