I can't if there's no sugar, it's just weird. I even tried stevia based coke once. Feels like something is missing. Like alcohol free beer. Or caffeine free coffee. Ditto for carbonation or temperature. I like it carbonated and cold.
Frankly I used to drink tons of coke many years ago. Like 2 liters a day. Of course this wasn't good at all. Then I stopped for many years and like an year ago I started the 1-2 cans a day. That being said some days I drink none so it's not like I need to. At the time I drank 2 liters I knew a guy who drank 4 and no water(literally chugging coke all day), and then he had some kidney problems and had to stop. No idea if he ever started again.
As for liquor - I am not an expert so I go for the simple stuff.
Absolut or Finlandia for vodka. For whiskey, I would pick Jack Daniels or Johnnie Walker. I drink rarely so a bottle lasts eons. I remember it toke me 3 months to down 750 ml of good rum. I think both whiskey and vodka go well with coke too or fruit juice. My idea of a no frills cocktail 😀