In Rehoboth -- For on the higher end side, I like Chez La Mer, Fusion and Eden. Back Porch is OK, as is La La Land, but I just like the others better. I have heard very good things about Espuma and Cultured Pearl, too.
Don't miss a dessert at La Crepes Suzette on Penny Lane, too. They make a banana, sour cream and brown sugar version that is to die for. They also make one with strawberries and nutella. Mmmm.
For not high end, I like Nicola (Pizza) and Gus & Gus. These are real (local) joints that serve up good food cheap.
We stayed in Rehoboth a couple of weeks ago and had some very nice food, Cafe Sole for lunch, Cloud 9 for dinner, food was very good service was excellent. Dinner at Abstractions, Sushi was VERY slow coming out but really good stuff and we also had a couple of curry dishes that were very good as well. Sunday brunch in Lewes at the Buttery, exceptional food and service.