Tough decision. As much as I like both, I'll have to go with tea.
I have trouble making coffee to fit my taste buds and have to ask my mother to make it for me most of the time. Though bitter, with the right amount of sweetness, coffee tastes lovely. One of the problems I have with coffee is the after taste it leaves in your mouth. It's usually bitter.
Tea is something I'll always enjoy. I've had quite a few that I can name: milk tea, Turkish chai, Indian Chai, green tea, jasmine tea and I can say I've liked all of them for their own taste and I have tea on a regular basis. This gives me the reason to pick tea over coffee. =]