We didn't allow our kids to have soda until they were six. Having waited that long, neither one of them like it (I think it is the carbonation they don't like).
We mainly drink milk, water, and the kids really like the new Capri Sun Waters, it is a low calorie version of Capri Sun (mainly water, I think only 35 calories). When we go to a restaurant, they usually get the pink lemonade or fruit punch ( I know they are no better than soda, they just like them better)
I just didn't feel they needed soda before then, but I'm not a soda drinker myself.
Like most people said, there is as much sugar in lemonda and juice as soda. I do think it is sad though when you see a mother pour Mt. Dew in the baby bottle and give it to an infant (yes, I saw this once at an amusement park. I guess the mother wanted Mt. Dew and didn't want to pay for a second drink for the baby)