Here's some of my favorites:
First String (every time I'm down): Skullcreek Boathouse, One Hot Mama's, Smokehouse, Reilly's south end, Big Bamboo (happy hour), Palmetto Bay Sunrise Café (breakfast), Plantation Café (breakfast), and new favorite - Fishcamp.
Second String (decent food): San Miguel's, Aunt Chilada's, Salty Dog, Street Meet, Mellow Mushroom, Poseidon, Old Oyster Factory, Main Street Café, Mangiamo's, Guiseppe's, Skillets, Captain Woody's, Black Marlin, Up the Creek, Char Bar.
Not on my radar (some people love these, I didn't): Stacks pancakes, Nick's Steak and Seafood, Crazy Crab, Caretta Coffee Co.
Grab two Fork & Fun dining guides when you get there (one for the car, one for the villa) and just have fun finding "your' new favorites.