One recomended restaurants would be the Oceanarium at the Pacific Beach Hotel www.pacificbeachhotel.com. They have an excellent buffet breakfast there. This restaurant is located in the Oceanarium Tower of the Pacific Beach Hotel on Liliuokalani Ave. between Kuhio and Kalakaua Ave. There is one part of the huge 3-story 280,000 gallon "oceanarium" in the restaurant that has a vast array of different types of fish that you can think of!! Some of them are only found in Hawaiian waters. The buffet is huge, and a vast array of different foods to choose from. Hot and cold foods, breads, desserts, fruit, juices, etc... good food, and you will not go away from there hungry!!  

Another great restaurant (this one would be "off the beaten path", so to speak), would be the Seaside Bar and Grill. It is located on the corners of Seaside and Kuhio Ave. The food is good, and not very expensive. It is right on thebus schedule, so you really cannot miss it.

Cheeseburger in Paradise (Waikiki )  www.cheeseburgerland.com is another good place to eat. There is entertainment in the evenings, and is right directly on Kalakaua Ave. Great food, good prices. The burgers are huge! And the large serving of french fries to boot!! The prices are not bad at all, considering the amount of food that you get to eat and enjoy!! 

Duke's Canoe Club www.hulapie.com is another great place to eat. The breakfast buffet is quite nice, and you can sit at a table right on the beach to enjoy the fabulous ocean views! Diners love the "cooked to order eggs" and  their eggs benedict.

Chucks Steakhouse http://www.chuckssteakhouse.com has good Mai-Tais, great steaks and a serve yourself salad bar.  This is a relaxed place to linger over a drink and watch the beach scene.   Also has a great breakfast.  Sit on the verandah for the best view of the beach and diamond head at sunset.  You'll feel like you have truly arrived in Honolulu.