I don't care for any of them except the chocolate ones , but I have to KNOW IT, since I drink my plain coffee black, but the flavored ones NEED cream/milk and sugar.
that being said, take one of those single serving packets of instant coffee (Sanka gives the best flavor but lacks the caffeine )and mix it with instant Hot chocolate mix. (No marshmallows, I made that mistake once ) If you need to stay awake it's double the caffeine with out souring your stomach with the acid of straight coffee.