What Type of Tea is the Best to Drink?

Today at work i drink like five cups of green tea for some reason ( i dunno why), any ways after i drink it all i felt really elevated like my mental processes were all sped up and i was really sharp and on point, i got all my work done and did a really good job (could have been the sugar though, i put 2 tea spoons in each cup). But my main question is: what tea (with out so much sugar) is REALLY good for you? Like what tea, if i drank every day would i be able to notice some good changes in my energy and mind state, is there? Any help appreciated. Thank you.