Here are a few suggestions from things I've found fun and interesting. I'm very excited for you taking your first trip. You will LOVE this place!!!
From MK, take boat ride to Wilderness Lodge, see the geyser, eat a meal, take a picture on the bridge inside the lobby and by the fun totem pole outside the mercantile, sit by the huge fireplace, walk over to Ft. Wilderness, do the campfire and movie, visit the petting zoo.
Definitely Animal Kingdom Lodge to see the animals, have a zebra dome, browse their awesome gift shop, hear the storyteller by the firepit.
Poly-go at night and sit on the beach to watch the Electric Water Parade
Contemporary-supposedly has the best arcade around, if your kids would like that, eat at Chef Mickey's.
From DTD, take the boat to POR, see the waterwheel, roam the peaceful premises, walk the path to POFQ, very pretty architecture, have a beignet, take pictures by the gators playing the musical instruments.
Since you'll be at Movies, be sure to see the grounds of Music and Sports, which will be right beside you.
Pop Century-neat icons to have pictures with, Goofy water jets and Mr. and Mrs. Potato Head are especially good for pictures with the kids, have a tie-dyed cheesecake, check out the shadow boxes of the different decades in the lobby, the adults will especially like those, Everything Pop is a very good gift shop.
Coronado Springs is a beautiful place, check out Buzz2001's information on it. It is really a beautiful place and has some unique stuff in its gift shop.
Grand Floridian-just see it because it is there, top notch, and probably the most well-known resort in WDW.
Caribbean Beach-I haven't been to this one, so it's on my list to do this summer. Looks like a good place to get the real beach atmosphere.
Spend some time walking along the Boardwalk at night for a fun atmosphere, games and ice cream, etc.