My favorite drink during non-F&W times is an Innis & Gunn from the beer stand next to the check-in desk for Rose & Crown.
During F&W, my favorite is the Frozen Brown Elephant from the Refreshment Cool Post between Germany and China. It's a frozen Coke slushie with cream liqueur doused on top. It sounds really odd, and like it would not be the best combination, but it is delicious and refreshing!