I used to drink a few sodas a day, and I switched to tea about five years ago. I lost some weight during the first year, but I've found I have more energy with tea and no crash. I get most of my tea from Adagio (I'm not affiliated).

I'm a sucker for Irish or Scottish breakfast. Generally I like the black teas which have higher caffeine. Tea to me seems to be less abrasive than the sugary high caffeine drinks but just as effective ;)