Book. Your meals. Now.
EPCOT = favorite park. Assume you'll be visiting it a lot.
Le Cellier - Yes, yes and again YES! And have the maple creme brulee. So-called because you will "creme" when you taste that brulee. It's that good. No really. And the cheese soup (made with bacon!) is not to be missed.
We loved the Biergarten. Partly for the food & entertainment, and partly because it was one place you had a shot at getting into on a day when you were lacking in ressies (especially if it's like 3pm when there might be openings) But really, we liked the food too.
Coral Reef in The Seas is one you need ressies for and is worth a visit. Try to get a table next to the fish tank, though all have a view of it.
Oh yeah, ride their Nemo.
Norway had great sweet pretzels.
RAIN GEAR! At the very least, a spare set of tennis shoes for when yours get soaked and won't dry out by the next day.
MK seems to be the hardest place to eat. Try to score ressies at the Liberty Tree.
Whispering Canyon is great, we recommend breakfast - they have this (as we call it) skillet of doom filled with all manner of good things including biscuits baked by southerners who know how to do such things. But if they offer you ketchup.... accept >
Also, the Wilderness Lodge has Humphrey Bear merchandise. How can you say no to that?
The water parks are great. If your pass includes them, try to visit at least one.