What drink can I substitute for diet coke which has "taste"?

After reading all of the warnings about diet coke (caffeine and acid) here on Fluther, I would like to give it up (after drinking 6 glasses of it per day for over 25 years). But I cannot find a satisfactory substitute that contains little or no sugar, no caffeine and no acid that still tastes good. I wish that was water, but water is just plain boring. Any good ideas? Thanks!