The missus and I go every year around our anniversary and we have eatin at CRT, LeCellier, San Angel Inn, and Coral Reef for all 3+1 our anniversary dinners.
Of the four I would have to say Coral Reef was my favorite. You can get personalized menus and a diver to dive down near your table with a little sign (we opted out of it, but it did happen while we were there). Just search the boards and you can find the contact info for Coral Reef. My wife also enjoyed it, she is a picky eater and found many things on the menu she would eat (with the removal of sauces), and found watching the fish to be fun.
Our least favorite was San Angle Inn. It was too crowded which spoiled the romance. Plus it was so dark we both had a hard time reading the menu and seeing our food. You know how it is after getting out of the Florida sun and walking into a dark place... The food was also not our thing.
Cinderellas Royal Table and Le Cellier are what they are, love 'em or leave 'em.
CRT has changed since we have been there with the picture package thing (I think) but it was nice. It was overpriced for the food that you got, but you are eating at the castle and your kids will be entertained. Le Cellier, I just don't buy into the hype. I can get a good cut of steak at home and pay less for it.
Out of those 4 I say Coral Reef.
