We will order whatever we feel like eating. Before adding the DDP to our July 2010 trip, I looked at the TS restaurants we will be going to, as well as the most likely choices for CS. I went to allears.net and looked at the menus. I added up the LEAST expensive choices from each category (entree, dessert, beverage), and added in tax. I did not take any snack credits into account. The basic DDP still saves us a good amount of money on a 10-night trip, even before factoring in any snacks. We will have 40 snack credits, and some $1 items could be considered a snack credit (a banana for example, something the boys, DH or I would possibly get for a midday snack anyway). So all I would have to do is add $40 to the total. The only reason I did not factor in snack credits was because I was trying to see how much we would save doing the DDP vs. paying OOP, and I am not sure exactly how many snacks we would buy over a 10-night trip, but I don't think it would be 40. I do know though, that we always get dessert with dinner on vacation (even not on vacation lots of times!), we always eat a TS dinner every night on vacation, and when touring a theme park we prefer a CS lunch. The only thing we might have done without is the CS dessert, but plenty of times I would get either fruit or a yogurt, something I normally have daily after I eat lunch. No one said I have to have ice cream, a cookie or cake every time! Even if I omit the least expensive dessert from all the CS lunches, we still come out ahead.
So, IMO, it is more important to order what you want, because to me that is the best value. If you are eating something you really don't want just because it is more expensive and you feel you are getting a better deal, think about it...is it really a better deal if it was not your first choice?