Once the park hours are out, we usually can figure out pretty easily which park we are going to be at when, since we try to make sure we hit each nightly show, favorite restaurants (Disney is all about eating for us, now), which parks we want to stay late at, etc. So that makes PS planning alot easier, since we know what we want to do... but, we also have a list of restaurants that we want to hit, as we're familiar with them all now, so that makes things tons easier, too.
I would figure out how much eating you want to do. We usually eat something in the room, unless we are doing a character breakfast (which I HIGHLY recommend doing at least once!), then a lunch and dinner... though it's often cheaper to eat a big lunch and counter service at dinner, we like being able to eat a quick lunch in the parks, go back to the rooms in the afternoon if we so desire, clean up and go out to a nice dinner. Each family is different in that respect.
My fave meals that *I* think are must hits are 'Ohana's, California Grill, 50's PT or Sci Fi, any of the world showcase places... If you want a character meal, Chef Mickeys and Crystal Palace I think are most popular, though we LOVED the Princess Storybook at Epcot this time around. We aren't much into the plush characters as much as the face ones. 1900 Park Faire is a great one, too, both for breakfast and dinner (both character meals).
My biggest suggestion is to really read through
www.allearsnet.com for menus and prices. If you see anything that looks appealing and worth your time, post for opinions on here... people are pretty honest =) If you still want to try it, see how you can work it in with your park hours once they are released.
Some people are completely content grabbing counter food, eating maybe one PS meal a trip, and just taking a chance on getting in without a PS... We've reached a point in which WDW is all about eating good, I guess because we're adults who've done all the parks... and we love to eat

You'll have a great time either way!