Personally, I'm pretty hardcore about drinking water, and I want my son to be the same. Drinking water is a crucial element of good health, but it's a habit hard to aquire in our culture.
That's why it's super important to try to make drinking water a part our children's lives so it will become a habit that will stay with them. My son is just an infant, so his primary drink is formula (I am unable to breastfeed due to medical reasons), but I'm trying to get him into the habit of drinking water by providing it in his sippy cup throughout the day. I also have him drink it while I feed him solid foods.
Some people think it's acceptable to give young children, even infants, soda. I'm going to get on my high horse and say that it's absolutely not okay to do so. Soda is full of sugar (and not just any sugar, high fructose corn syrup!), caffiene, and a bunch of other crap that is terrible for young teeth and young bodies.
Beyond that, giving your child any flavored drink on a regular basis is setting him up for thinking that everything he drinks should be flavored. This will mean more work to keep him on a healthy diet when he's older. You'll also be setting yourself up for higher grocery bills to sooth his desire for flavored drinks when he could be consuming mostly water.
If you're already in this situation, I know from experience that you're not doomed. My siblings and I were raised in the same household, drinking and loving soda from a young age. Although I have a small addiction to soda, my drink of choice is water. And my teenage sister is the same way due to my overzealous water preaching. Now as far as my 13 year old brother...he may be doomed!
One thing I have found that works for kids (including my 9-year-old nephew) who hate water is Propel Vitamin Enhanced powder packets. These flavored packets are added to water and make them taste good. They also add some vitamins to the water, and with a suger content of 2 grams per serving, they are aren't a bad substitute for plain ol' water if your kid drinks it happily.