Hands down, a wedge of Parmigiano-Reggiano cheese is one of the world's great eating cheeses. At its best, you will keep going back for more and more and more. The true Parmigiano can be produced only in five provinces of northern Italy's Emilia-Romagna region. Try to make the cheese outside this collection of micro climates, and it is different.
Cheesemakers still fashion every wheel by hand as they've done for 800 years. Each wheel will taste different depending upon a raft of variables: the style and skill of the cheesemaker, the milk, whether it's a valley or mountain cheese, what time of year it's produced and its age. In a world where mass-produced mediocrity is rapidly becoming the standard, foods like Parmigiano-Reggiano are pure gold. Celebrate them.
Because of these variables, not all Parmigiano-Reggiano is alike. This cheese won't be cheap, but you will never forget the pleasure of it. Store it wrapped in plastic wrap and then in foil in the refrigerator. But serve Parmigiano-Reggiano at room temperature. Never freeze any cheese, especially this one. Reveal its characteristic shale-like consistency by breaking out chunks with the end of a knife rather than slicing it. Shave thick furls over salads, and serve the cheese for dessert with ripe pears. If you do grate your Parmigiano, do it just before serving to experience all its natural moisture and goodness.
Here are two sources for Parmigiano-Reggiano and other specialty foods that I have personally used -- they are excellent.
This is one of New York City's exceptional sources for Italian cheeses. Lou DiPalo always has at least three wheels of Parmigiano-Reggiano from different seasons and areas open. He personally selects his cheeses in Italy. They are a small business and do only a little mail order, but phone and talk to Lou. Let him select pieces of cheese for you and for folks on your gift list. You won't be disappointed.
Zingerman's Ari Weinzweig personally tracks down cheesemakers, tasting, evaluating and selecting. Zingerman's sources excellent foods from all over, not solely Italy. (Their Forum Cabernet Sauvignon wine vinegar from Spain is so good you want to sip it from a spoon.) Their French and English cheeses are outstanding, but of course my heart is with the Parmigiano.