For me, it's Coca-Cola and Kahlua. I don't drink all that often, but when I do, that's my thing. I usually prefer just Coca-Cola itself, though. I can drink 4 20 ounce bottles of that in a day.
Also, it's good to be posting again. I wasn't able to log on for several days, but I'm back and this topic seems like a great place to start.