Here are my restaurant recommendations, based solely on my personal preferences... and 22+ years of enjoying their cuisine:
Café Alcazar (25 Granada St, Saint Augustine, FL 32084-4387) is a true hidden gem…and is definitely off the main tourist path. It is a small restaurant located in what was once the deep end of the world's largest indoor swimming pool, now the Lightener Museum building. The food is quite good (I love their curried chicken salad.) and the atmosphere is absolutely unique and very conducive to conversation. They don't take reservations and only serve lunch. If you have trouble finding them, you can phone them at 904-825-9948. Check out their Trip Advisor reviews: http://tinyurl.com/5qlvrq
Old City House http://www.oldcityhouse.com/
Outstanding breakfasts and dinners. Located just steps away from the Casa Monica.
The Raintree http://www.raintreerestaurant.com/
The Reef http://www.thereefstaugustine.com/index.html?
The food is very good, and the ocean views are even better. Be sure to arrive before sunset (or for Sunday brunch) for best views. Request a window table when making your reservation.
(My personal favorite for ambiance and value combined)
Gypsy Cab Co. http://www.gypsycab.com/
Creekside Dinery http://www.creeksidedinery.com/
Le Pavillion http://www.lepav.com/
Purple Olive http://www.purple-olive.com
This tiny restaurant offers fresh, organic ingredients to make the most delicious Mayan dishes.
17 Hypolita St
St Augustine, FL 32084
And, for a special treat...you should try Collage http://www.collagestaug.com/ It is strictly a special occasion restaurant, but if you like good service, warm & relaxing ambiance and a creative, eclectic menu, this restaurant is a wonderful experience. They do everything right!
(Perhaps the best shrimp in town. ZERO ambiance, no reservations, reasonable prices)
You'll notice that I did not mention the Columbia restaurant. IMO, their food is good, but not as good as any of the other restaurants I have mentioned.
Also, it is somewhat of a tourist trap and one of about 6-8 other Columbia's around the state. This may qualify them as a chain restaurant. I know a lot of people eat there, but the other restaurants I have given you are all better.