Had to vote liquor. Was tempted to go with wine as it is pretty versatile. Still sort of wish I could change my vote. But wine is kind of cheating because I wouldn't be able to go with just one kind of wine - I'd want red wine with meals and happy hours, white wine with summer bbqs and sporting events.
So I went with liquor because if I had to go with just one drink forever for the rest of my life, it would be the gin and tonic. It's great with foods and is a nice palate cleanser, it's ideal for happy hour, and I can drink it as an after-dinner drink too. Might feel a little bit like a lush having a G&T at the ballpark, but sometimes you've just gotta do what you've gotta do.
While I enjoy the occasional beer, it's not something I like very often.