Without restriction my top 3 are... Blue Water Grill, Blue Moon, Kill Devil Grill
Tortuga's Lie, Fish Heads, and Food Dudes Kitchen have never let us down, either. We've only had lunch at Food Dudes. Avenue Waterfront Grille in Manteo was excellent the one time we've been. We'll be back, but haven't been there enough to comment on consistency.
Tim-OBX mentioned Salt Box. I always forget about that place as it's far enough off the beach to be out of sight, out of mind, but their food is amazing as well.
I generally try a new item every time I go to places and would recommend anything on the menu that looks good to you at the above places.