I don't drink all that much soda, maybe 4-5 cans a week, but I only drink diet sodas with artificial sweeteners. This has been my practice for 20 years.

The reason has little to do with calories but with the fact that I suffer from gastroesophageal reflux disease (GERD). Drinking soda with sugar or HFCS gives me severe heartburn. Some say that the artificial sweeteners aren't good for you either but I'm not concerned given my limited consumption.