Too many "Diet" choices.

If your diabetic then diet versus non-diet does make a difference.

The theme these days seems to be:
• Traditional artificial sweetener (Aspartame). The 'classic' diet formula.
• New artificial sweetener (Splenda a.k.a. Sucralose). A 'left-handed' sugar that supposedly tastes more like natural sucrose. In the United States, most everything is sweetened with High Fructose Corn Syrup, which tastes different than something sweetened with Sucrose. So, while these 'new diet' formulas are geared to taste like the real thing, they don't.
• The half-and-half Sucralose/Fructose or Sucralose/Sucrose. Pepsi Edge and Coke C2 are examples of these. The idea is to cut the calorie contribution from sugar by 1/2 without harming the flavor too much.

For me, its really a moot issue. I don't drink nearly as much soda as I used to. Instead I opt for juices, unsweetened teas or teas sweetened with sucrose, black coffee, or ice cold water.

Jam it back in, in the dark.

Originally Posted by Sousuke

Then there's the people who will go to McDonald's, order a large fry and a Big Mac, and... a diet Coke. Why? I don't think we'll ever know.

That makes sense if you are diabetic. Simple sugars affect blood-glucose levels in a very short period of time, and are difficult to manage with insulin just before a meal. I dated a Type I for two and a half years; she had a very convenient insulin pump that meant no fumbling with needles. She simply too her blood sugar, estimated the glycemic impact of what she was going to eat and adjusted the flow of insulin accordingly. For starches and complex carbs, its not a problem; simple sugars could take her from normal blood-sugar levels to hyperglycemic in 30 minutes or less.

If you believe the published nutrition facts:

Big Mac: 35g Carbohydrates, 7g Sugars, 600 Calories
Large Fries: 40g Carbohydrates, 0g Sugars, 540 Calories
32 oz Coke: 108g Carbohydrates, 108g Sugars, 400 Calories

So it makes sense for someone sensitive to simple sugars to get the diet coke with the Big Mac and the Large Fries. You cut out approximately 94% of the sugar.

There's nowhere I can't reach.