One restaurant that may be relatively unknown is Basmati's on 30A.
It has an Asian flair with very good sushi to start the meal. The servings are adequate, not huge, and in visiting the restaurant 10 times or so in the past few months I have never been disappointed in any meal I have ordered.
It isn't cheap. By the time a couple has a small order of sushi, wine and an entree, the bill will easily come to $100 or so. It is small so if you are planning to go during a time likely to be busy, call in advance for reservations.