I second the suggestion to go to O'Steen's. The fried shrimp is like no other! Batter is very light and the shrimp is fabulous! Stinkin' Good in my book! Be sure to dip it in the pink sauce and add a bit of the Datil Pepper sauce in the green bottle if you like some heat. No reservations, no credit cards and often a line. Go at an off time and you can usually get in pretty quickly. Bonus: right before O'Steen's (same side of the road) is a Whetstone Chocolate Shop. Yummm! They sell Hot Chocolate with Datil Peppers in it to die for and even a Datil Pepper chocolate candy. They serve ice cream as well. Both are just over the Bridge Of Lions.
If you haven't already, please try O'Steen's Restaurant in St. Augustine. Wonderful seafood and very popular with the locals. Just be prepared for a possible long wait. I guess it depends on what time of day you go. But it is worth the wait.
We spend a week + every June in St Augustine Beach and I've never noticed this place until this year, so I guess it's newer. Have you ever tried Seafood Kitchen of St Augustine, down A1A a few miles? Definitely worth checking out for a great value seafood meal.