Tea... the taste/smell of coffee is so disgusting to me that it makes me nautious for as long as I can remember. Even as an ingredient in food, there is something about coffee that is completely repulsive.
Used to be coffee, but now i am experimenting with green tea, i have found that it provides a milder effect but more lasting and it doesn't have the crash associated with coffee.
Both ... just not at the same time. That would be like crossing the streams!