I've definitely had moments in a long run where I'd love a Coke.

I'm not a big fan of Diet Coke. Once in a while, I'll have a Coke Zero. Even more rarely, I'll drink a real Coke, but water it down because the sugar/HFCS content is just over the top for my palate.

I don't keep any Coke variant at home though, and I don't carry money when I run, so I've never had the chance to indulge. My guilty pleasure is lemonade (Newman's Own, similarly watered down) after a run.