I really WANT to get off soda, but I can't. Good thing I'm nowhere near the age of most of you.
Yes, water is your friend. I drink a couple of large glasses of water before I go to bed each night, with lots of crushed ice in both. The bad thing is that I have to get up in the middle of the night to go to the bathroom.
Orange juice is great, and even better with crushed ice in it because after, the ice that's left has the orange juice flavor in it. Yum.
As for diet soda's, I hate diet Pepsi, and used to like diet coke. But diet Sprite is disgusting, although I don't like Spite that much to begin with.
I have to try putting regular vanilla in regular coke to see what it's like.

Cavity-wise, I've had many, but that's not entirely my fault. I have hypo-plastic teeth or something, which means alot of my molars have less enamel on them than regualr teeth, so i'm more prone to cavities. Not only that, but I think three or four of my teeth actually came in with cavities on them. My mom also had this so it's all her fault. Mean old witch....