We found the "Emerald City" cache today. Here's a brief description of various sweeteners (taken in part from an excellent Beachbody Nutrition article):

Sucralose (Splenda): animal tested, calorie-free, and FDA approved. Too new to know of long-term effects, however. Tell-tale aftertaste for about half the population.

Sugar Alcohols (Xylitol, Sorbitol, Mannitol)/Tagatose (Naturlose): Some calories; FDA approved. Causes flatulence, bloating, and diarrhea. Yucka.

Aspartame (NutraSweet, Equal): calorie-free, FDA approved. Can cause headaches. Many people think it's harmful (science is undecided, however).

Acesulfame (Sunett): causes rodent tumors. Aftertaste.

Stevia: not a chemical - it's an herb. Not approved by the FDA, but available as a 'health food supplement'. Causes reproductive side effects in rodents.

Saccharin (Sweet'N Low): caused cancer in Canadian rats once, so the FDA tried (unsuccessfully) to ban it. Generally considered safe now, however.

Sugar/Corn Syrup: sucrose, glucose, dextrose, fructose - they can all make you fat, which is a major cause of type 2 diabetes and cardiovascular disease. Makes kids hyper, then extremely emotional. Cheaper than the others, however.

Take your pick.   =(

UPDATE: Here is another excellent article on these substances.