We just returned from a trip to Oahu. I had originally made reservations at quite a few high-end restaurants (Chef Mavro and La Mer), but canceled them in favor of a wonderful Japanese soba noodle restaurant Matsugen. At lunch, you get an incredible deal for $13.80.
Other finds and thoughts:
3660 On The Rise - chef driven restaurant with wonderful food - portion size huge - you can easily split courses
Mitch's Sushi Bar - a perfect place to go right from the airport. Must make reservations. BYO only, but there is a liquor store around the block.
Hiroshi Eurasian Tapas - super wine list and perfect food to share
Alan Wong's - I was disappointed and next time I would not do a tasting menu, but order a la carte instead. Portion size also huge.
Hee Hing - the worst dim sum I have ever had
Elua - OK
Pictures and full descriptions here: