For sweetness, try rotating between non-fructuse sweeteners. like saccharin, aspartame, stevia, etc.
I also find that Coke Zero is a nice way to cut down on sugar but still keep the Coke taste, and it's a lot less acidic than Diet Coke. However I don't find vending machines stocking it as often as I'd like. That's assuming you are not buying into the aspartame myths. I've got diabetes in my family, so to me the risks of sugar far outweighs the less than slight risk of aspartame.
Or, you know, stop drinking sweet things =) I know that's heretical in our society, but once you cut out sweet things your palate will change and you'll find things like unsweetened teas (cold Oolong is fucking amazing) and juice/water mixes are cheap, simple, tasty and healthy.
I love unsweetened iced tea and drink it as often as I can get it when I'm visiting home in the States, but it's so hard to get good iced tea in Europe, and since it's hard to keep enough ice on hand, it's a pain to try and make it here as well. So I end up drinking stuff like Pepsi Max (Can't get Diet Pepsi in Norway) or other diet sodas.
Actually I can't eat aspartame because it severely upsets my stomach, so I need to avoid it completely. Even things like chewing gum with aspartame cause my stomach to get really upset. I think the best solution is simply not eat as much sugar as possible. I was on South Beach diet several years ago, and I actually lost 20 lbs in 5 months, so maybe I will do something similar.
In terms of acidity it's the other way around. From the article:
"say you have two liquids, like Diet Coke and Coke Zero. Diet Coke has a pH of 4. Coke Zero has a pH of 3. Since pH measurements are logarithmic, this means that Coke Zero is ten times more acidic than Diet Coke."
