Mostly coffee for me since going through writing up, although since relaxing a bit over Christmas I have started to drink tea again and am about 50:50 at the moment.
Did also experiment with Green tea, it was alright, a friend of mine used to come to our lab office with a bag of loose leaf green tea, which looked just like marijuana, and asked if i wanted to go outside and do a bit of green. He was actually referring to partaking in a cup of green tea on the bench outside the lab.