I'm partial to an Espresso Tonic (espresso in tonic water with lemon and simple syrup) or a Lemonade Americano (two shots of espresso in a lemonade), but just in general I love Americanos (espresso in hot water), Red Eyes (espresso in black coffee), Black Eyes (four shots of espresso in black coffee), Espresso Martinis - just any drink that has espresso but no dairy element. Call it "caffeine-maxing" or whatever, but that is my preferred way to drink coffee when I can go somewhere fun.
Shout out Amherst Coffee in Amherst, Massachusetts, you'll always be my favorite!