Replying to Switching from coffee to tea

So I have always been a big coffee drinker and drink mountain dew a lot and I'm starting to see its effects. It really became apparent during finals week when I was drinking a lot of caffine. lately unless i drink a full cup of coffee in the morning i get huge headaches, the aspirin with caffine is ok and works but i was thinking about switching over to tea. If you guys drink a lot of tea what flavors do you guys like. Any recommendations would be great!