Hukilau Cafe in Laie - Really good breakfasts, and okay lunches.
Cholo's in Haleiwa - best Mexican food on the island. I know...Mexican food in Hawaii. But it's pretty good.
Make sure to get some shave ice. Matsumoto's is the original, but the lines can be pretty long there just because they're the original. We really liked the shave ice shop by Seven Brothers in Kahuku as well.