Newport- special occasion lunch
I agree with Castle Hill although depending on when you go, you can have very different experiences. My wife and I have done our anniversary there for years. Generally on weekday nights. It is peaceful, amazing views, amazing service, and amazing food. Two years ago we went on a Friday night and the outdoor patio bar was hopping with cougars that had drank to much and the table next to us seemed like they were directly off of the set of the housewifes of New Jersey, it was not conducive to a romantic anniversary experience. All of our experiences there have been top notch.
Last year we went to the Spiced Pear at the Chanler and it was awesome. I thought the view at Castle Hill was better. Chanler was a spectacular meal with wine pairings (generous pours) really really expensive.
I have heard good things about Tallulah on Thames.
The Boat House (I think that is what it is called, it is in the same group as Castle Hill, Newport Restaurant Group) is very very good as well. More of a harbor view but very good food and very good service.
Went to Perro Salado in October and the food and service were both very good. Not nearly as fancy as the first two but good and fun.