While preparing this excellent recipe I tried a new cheese: Grana Padano (Grainy Cheese of the River). A hard, cow's milk cheese - it provides a great alternative (or addition) to Parmesan and other hard cheeses. Although younger, cheaper, and less flavorful than Parmesan it still has many merits: in the case of the "Cacio e Pepe" recipe nicely balancing the sharper Pecorino. It is also readily available and non-brand specific. Jenkins finds Grana Padano lackluster (describing it as a "serviceable grating cheese"), but I found it outstanding for salads, sauces, and sautes - much more supple than hard cheeses with more personality. Give "Cacio e Pepe" a shot or simply try out a new, different hard cheese.
Any other non-parm cheeses out there that folks enjoy?