We just got back from WDW...stayed at the Polynesian. Loved it.
We paid for the dining plan and it was like $90.00 /day for two adults and two children ages 6 and 3. We thought it was well worth it. It includes one snack (drink; or chips; or ice cream, etc.); one counter service meal (example, hot dog; fries; dessert; and drink); and one table service meal (includes appetizer, entree, dessert, and drink).
For four people you receive four points for each category per day; so for four people and a six day stay; you receive 24 snacks; 24 counter service meals; and 24 table service meals. There is no discrimination on when or how you use the points. A disney waitress gave us a VERY IMPORTANT HINT that I wished I knew earlier. If you wish to dine at an expensive restaurant (which counts as two points/person rather than one point), use the points toward the adult meals and pay for the much less expensive kids meals. We did this at the Brown Derby (MGM) and at, my favorite, The California Grill (Contemporary). I would highly recommend either of these restaurants...especially the California Grill (try to get reservations for about 7:30 so you can watch fireworks...call now).
Anyway, an example of the cost of the food is as follows;
a snack is $2-$3 each; a counter service meal (child or adult) is about $10; and a table service meal for a child is about $10 and from $20-$60/per adult.
We went to the restaurant in Cinderellas Castle during the extra magic hours at the Magic Kingdom and our bill came out to $145.00 for all four of us. We used the dining plan and for some reason this meal only counted as one point for each person (the guide says it should be 2 pts.). And our hot dogs earlier in the day was about $35 for all four of us. So on this particular day we received at least $180 in food which actually cost us $90 using the dining plan.
Most all restaurants count as one point/person like the Crystal Palace at the Magic Kingdom...recommend this restaurant.
Another option if you like to sit down more than once per day...is to pay for the kids meals and use the points for the adult meals at one point restaurants; you can then sit down twice per day. Another thing, you can have three table service meals one day; and three counter service meals the next; and nothing the next day...you can use your points in any combination you want and when you want.
We found that the basic plan was all we could handle...my husband felt like we were eating quite a bit; but I felt like it was a free option to try expensive restaurants; and you could order the most expensive thing on the menu (filet mignon for me

) and get the most for your points.
I would definitely buy the dining plan again, but I would splurge at the California Grill at least twice and pay for the kids meals...
Good luck and have fun,
Cindy