For our Honeymoon we would have easily spent around $1000 on the food, if we ordered exactly what we ordered on the Dining Plan, which we managed to get for free.
We had no restrictions on the Dinining plan, except:
At most locations snacks must be priced under $5.00 with tax, all though there are exceptions to this rule, such as at most bakeries in the World Showcase.
No alcholic beverages of course (we don't drink anyway, so mo big deal for us, but of interesting note this does not apply to the Hoopde-Doo Musical Review where certain Alcholic Beverages are included in the price anyway)
And
Coral Reef Cafe Excluded Specialty Drinks
Here's the List of Sit Down restraunts that we ate at on the Dining Plan:
Cinderella's Royal Table (this takes 2 sit down dining plan certificates per meal, but worth it, you also get a photo with Cinderella included, which again is an exception to thier rule that photos are not to be included on the dining plan)
Prime Time Cafe
Coral Reef
Hoop Dee Doo
50's Prime Time Cafe
San Angel Inn
Princess Storybook
And the African Buffet in Animal Kingdom Lodge, but I can't remember the name of it right now.
Most of our Counter Servies meals were around $20 a plate as well.
Another tip is when you are having a large sitdown meal, to use only one Counter Service at a place that gives a lot of food, such as Cosmic Rays and order the Rib and Chicken Platter and share it between two people.