Hi Vicki!
Although any of the 4 are probably good selections, the 2 I hear frequently recommended for anniversary celebrations are the California Grill and Narcoossees. In addition to really good food, the locations for both is an attraction for special moments like these.
I've been to the California Grill twice (although not for anniversary), and the food, ambiance, etc. is really nice. To me, the California Grill offers the best view, overlooking Seven Seas Lagoon, and of course Magic Kingdom and Cinderella's castle (and the Fireworks :-)..And I do mean "overlooking," as the restaurant is on the 15th floor of the Contemporary! The goat cheese ravioli, pork tenderloin, and creme brulee is to die for! Although I haven't tried it, many say the bison is good there also.
Although I've never been to Narcoosees, friends that I know have been there for their anniversary and said they had an excellent experience! The location is at the Grand Floridian, which in itself has a romantic quality when you're in the resort. Narcoosees also has tables with window views to catch the fireworks. My friends loved the lobster and surf and turf.
Whichever you choose, make sure to mention it is your anniversary. Sometimes they'll do something a little extra special for you. Ask for a seat by the window, and plan your reservation to where you're seated comfortably for the Wishes fireworks (show times historically are 9:30 or 10, depending on the season).
Hope that helps! Have a terrific, magical anniversary!