The OtterBox Agility Shell ($40) is the epicenter of the entire Agility system; none of the products in the Agility line will work without the Shell, as the large hole on the back of the Shell is designed for attaching the other accessories in the system. The Shell is made of hard plastic and doesn’t feature a rubber lining as seen in other OtterBox cases. Nothing is subtle with the Agility Shell — it’s huge, hard, tough, and too pointy. The…