Which beverage will have the greatest effect on demineralization of your teeth?

Acids. Soda, even diet soda are prime offenders as preciously mentioned. But don't forget energy drinks, like gatorade , bottled teas, juice drinks are highly acidic and very destructive to teeth. It is not only the amount of sugar but the nature of the acid in the drink that effects teeth. Drink more water.
Acid beverages. The more acidic the more demineralization and of course the slower you drink the more the teeth are bathed in the acid environment.
Lemonade,fruit juice. Sometimes "all natural" products are far more problematic than commercial drinks. While the media is always touting soda's even those with artificial sweeteners as being the "bad guys." citric acid based all natural drinks like lemonade, or orange juice and grapefruit juice have the most potential to demineralize teeth !
Acid in drinks. You can research this for yourself online. Recent studies suggest most sports drinks see: http://edition.Cnn.Com/2009/health/07/23/teeth.Erosion.Drinks/?Imw=y.
Soda. Soda is the absolute worst because it is acidic and contains sugar. The sugar is food for plaque bacteria which create plaque. Plaque equals even more acidity. It's the perfect storm for demineralization.
Mountain Dew. High sugar, carbonated drinks can really damage the teeth. Sodas cause a lot of havoc, but especially the one's like mountain dew, jolt, etc. Acidic beverages/foods like juices, lemons, also have a damaging effect.
Hands down, soda. The more acidic the drink, the worse it is for your teeth. Soda (any type) is one of the most acidic drinks available. Gatorade and other sports drinks are not to far behind. Our teeth are "designed" to recover from some acid exsposure, but these drinks in particular can overwhelm the system and cause severe demineralization.
Anything acid. Teeth can thin the outer coating with acid ingestion. Therefore soda pop is a prime offender. Most other foods are not in the mouth long enough to do this. You could suffer if your calcium gets too low and deminerlization occurs in those with salivary gland failure of secretion (dry mouth). Have your dentist check your mouth of this is a concern.