Basilio is the the greatest version of a beach side shanty: one filled with delicious food. Basilio is leterally right on the beach
The Belvue is more of a bar than a proper restaurant, however, just for the view alone, its worth a visit
Loctaed in the center of Marbella, overlooking plaza Delfín, is Bistro Del Parque, a traditional spanish tavern that specializes in andalusian tapas and rations
Funky is slightly outside of Marbella, but if you are in the area, or headed that way it's one of the better places you will find for a bite to eat.