peccorino romano - it's a bit like parmesan, but cheaper, more salty, and a bit less flavorful. I'm from an Italian family which used to be rather poor, so everyone got used to eating it instead of the more expensive parmesan (in Italian families grated cheese is a way of life), and by the time I came around they were all just too used to it to ever bother with parmesan. It's my favorite by far, even above mozzarella and provolone, and parmesan. Tastiest if you get a chunk of it before grating and stick it in a hot oven for a moment, just enough for it to start to melt.