For only adults, we think that Citrico's is the best. California Grill (in time for fireworks), Narcoossee's, Flying Fish, Brown Derby, and Wolfgang Pucks are great spots with few young kids. At EPCOT, we always go to Le Cellier.
Part of the WDW magic is being around chilidren and families. For that experience, I suggest the CP lunch with Pooh and friends, Cape May Cafe Seafood Buffet, and The Liberty Tree Tavern.
A great evening could be a nice early dinner at the Flying Fish (no dessert), rent The Breathless for a spin around the lake and watch Illuminations. After the cruise, dessert at Beaches and Cream, walk around the lake, and finish the evening at Jellyrolls or Atlantic Dance Hall. Unless you are staying at an EPCOT resort, take a cab back to your resort.