We just returned from a week in Kailua, which we HIGHLY recommend if you're looking for a low-key (read: non-Waikiki) experience. Our ocean-view cottage was reasonably priced and we loved having our own beach on a quiet street (and no streetlights - a revelation for those of us used to always-bright city living).
Pinky's became our de facto hangout. Overall, I'd give the food about a 6.5 - 7, but the pupu (appetizer) selection was good and the menu had something for everyone in our rather diverse group. The specialty drinks have a nice kick and come in giant Henry the Eighth-sized goblets. We were also impressed with the staff - everyone was friendly and the manager quickly remedied a minor problem. By the end of our trip they knew us and we hated to say goodbye the last night.
We also visited Buzz's twice. I ordered local specialty fish and they were wonderful, and the others in our group very much liked the steaks. Beware of the Mai Tai's - they're strong like gasoline and pack quite a punch.
We did breakfast once at Boots and Kimo's and very much liked the famous macadamia nut pancakes. My husband was also pleased to find guava juice on the menu. We'd heard mixed reviews on the food and wait times, but an 8am weekday visit was just fine.
We ended up frequenting Agnes' Portugese Bakery. The pastry selection was wonderful, the coffee was hot and plentiful, and the place is spotless. It looks like a family-run operation and we just loved it. We didn't get the try the malasadas, but when a family with several small children came in they were all shouting "I want my malasada!" so we figured that meant something special.
We also stopped at Breaker's in Hale 'iwa during a rainy day on the North Shore; again, the food was just a bit above average but the friendly staff made up for it.
My sister reported good things on Romy's and Giovanni's shrimp trucks in the Kuhuku area. Note that Romy's is actually the only one in that stretch that uses locally grown shrimp.
Lastly, a big plug for the Kalapawai Market just north of the Kailua public beach. Surprisingly large beer and wine selection, and our 2 experiences with their deli sandwiches were excellent.
We're already planning a return trip!