We were introduced to Disney World by some friends that have been going for DECADES, and we've gone with them six or eight times. What they taught us, and we've found works well:
Look on TourGuideMike.com (or some other planing site) for least crowded days in each park, to determine what days you want to be in which park. From here, we make -one- sit-down meal reservation, to make sure 1) we get into our favorite restaurant(s), and 2) that we get to eat at a reasonable hour.
SO, while on vacation, we'll usually grab a quick breakfast on the way to the park (muffins, bagels, Clif bars, etc.), one full-service meal (per our reservation, either lunch or dinner), then for the other meal we'll either just snack, or hit a counter-service restaurant. This way, you're only having to coordinate around one "appointment." Also keep in mind, unless it's a Character dining meal (where you paid up-front when you made the reservation), you -don't have to- show up for your reservation.
We purchased the dining plan once (when we went without the other family), and decided that we'll never do that again. Agreed: too much food, and not really worth it. Tables in Wonderland is a membership you can purchase, that gets you discounts at lots of restaurants. It worked great, when we were traveling with four adults and five kids.
Happy traveling!
M.