Your poll is kind of ambiguous since the diet sodas also come in flavors like lime and vanilla.
At any rate, I usually get some variation on diet soda. Regular soda is too sweet for me now, and I don't want to gain weight from the soda habit.
Vanilla coke in a can is ok, but can not even come close to comparing to one made by a fountain jerk as they did in the 50's. (They had a 1950's style diner at penn state which made really good flavored cokes).