On Singer Island, the choices are, IMHO, limited.
Johnny Longboats serves breakfast, lunch and supper. My opinion is there overpriced and average in quality.
2 Drunken Goats: In the past we've had a couple of good meals. Prices are a little on the high side, food is maybe a little better than average, nice patio seating. Service can be spotty. We stopped going when we were seated at a table and, after 20 minutes with not so much as a glass of water placed on the table, we left and haven't been back.
Sailfish Marina: Very nice location and views of the Marina. High prices for the quality of food they serve. We'll occasionally go for breakfast, every now and again for lunch but almost never for dinner anymore.
Up the road about 5 miles is one of our more favorite restaurants called Jetty's. We like to get there around 5 PM and sit on the patio overlooking the inlet and Jupiter Lighthouse. The food has always been good, prices a little high, atmosphere wonderful and service has always been good.
There are also several good options on Clematis St. and City Place. City Place has everything from Panera Bread, Cheesecake factory, Starbucks up to a Ruth's Chris Steakhouse. So a little something for nearly every budget. Honestly, we haven't spent much time on Clematis street and it's been several years since we've eaten at any of the restaurants located in that area.
At the Breakers on Palm Beach Island you can enjoy a drink/meal in high class style at the Seafood Bar. It's not necessarily cheap but we do enjoy having a drink at the bar, which is a salt water aquarium (not as impressive as you might want to think) and people watch. The resort is impressive in it's opulence and guests who stay there (think Beverly Hills Hotel type guests).
There is a chain restaurant called Ra we enjoy in an outdoor mall called Downtown at the Gardens. Grimaldi's Pizza has a restaurant there (we really didn't care for their style of pizza).
TooJay's Deli is also located in this mall along with a Whole Foods if you want that sort of grocery shopping. TooJay's is great for breakfast and not bad for lunch. There is also a Cheesecake Factory and many other chain restaurants in the Downtown at the Gardens mall.
Coconut's on the Beach in the Hilton Hotel close to Oceana Palms isn't bad. Nice patio seating overlooking the ocean. It's not great either but you could do worse.