What: The Insalata Caprese, made with buffalo mozzarella, plum tomatoes, and fresh basil, and often onions, olive oil, and balsamic vinegar.
It can be made as shown in this perfect demonstration by Coolio:
Why: Look good? Taste good? Smell good? Is good, Shaka Zulu! The Caprese, so named because it comes from the Isle of Capri, might get on this list solely because it's designed to mirror the colors of the Italian national flag (not Mexican, as Coolio jokes). But obviously, it's the taste that counts. The Caprese sets off the sharpness of the tomato with the richness of the mozzarella, and in the American style, highlights it with a shock of balsamic vinegar. All the ingredients are cut into pieces rarely bigger than a silver dollar, so it's easy to spear a leaf of basil, a slice of tomato, and a wedge of mozzarella with a toothpick, and pop the whole delicious morsel into your mouth at once. (And no, I don't know what's in Coolio's dime bag of special spices.)
Impact: The Caprese is most people's first realization that there are two types of mozzarella: mozzarella made from cow's milk, which is only good for melting on pizza or frying in stick form, and mozzarella made from water buffalo's milk, which is the food of the gods. Buffalo mozzarella comes in a golfball-sized clump, which only lasts for a few days before it sours. You'll find it in the fresh cheese aisle, floating in brine. If you get some fresh from the region of Campania, stab a fork in a ball and eat it pronto. Or better yet, step your game up and make a Caprese, Geto Gourmet-style.
Personal Connection: On a trip to Italy to watch my fashion-designer stepsister get hitched, I ate my first Caprese in the shadow of the Duomo in Milan, and then immediately ordered another Caprese at each of my next five meals in Milan and Florence thereafter. Usually it came (whatever the hour) with the richest, most luxurious red wine I've ever had, and when I asked for the label so I could buy a bottle, I was told, "Fah! You would not want this. It is just a house wine." And that, dear readers, is why you should go to central Italy right now.
Other Contenders: Garlic bread; French onion soup; Crab Rangoon; dolmades; pakoras; saganaki ("Oh my god! You killed it!").