The Americano is one of my favorite tall drinks. Although not as potent as it's younger sibling, the Negroni, the flavor is still very herbal, bitter sweet and orangey. It's the perfect aperitif for a hot summer afternoon while firing up the barbecue. And the low alcohol content means you can enjoy several Americanos without getting too drunk. (But it's still an acquired taste for those not used to Campari.)
The Negroni is one of my favorite classic cocktails. The flavor is very complex—a blend of herbal, bitter-sweetness and orange. It's very sophisticated, and for most people it's an acquired taste.