I personally love both. Which one I indulge in depends entirely on the time of day, my mood, what I've eaten, and the type of caffeine I need. But enough about me. I'm more interested in what the heroes and heroines in the latest books I've read drink.
Most of the time, I have no problem with their choice of coffee or tea. It seems to flow with the story. In historicals, I almost expect them to drink tea or hot chocolate. In westerns, it's coffee for the cowboys and tea for the ladies. In contemporaries, you get more variation, but there was a time where the hero in the book I was reading drank tea and it just bugged me for some reason. I felt that the big, alpha dude needed to be drinking coffee. He wasn't into health, organics, herbs or Zen. He had no cultural background that would lean him toward tea drinking.
For some reason, I think coffee fits universally with heroes and heroines, whereas tea you have to be careful with...down to the type. Tea can come off as feminine if not done right. Am I being unfair?
Coffee, tea, and the sexes. What do you think? What do you and your characters drink?