Do yourself a favor and make Duke's the first meal you eat when you arrive on Oahu. (And then, if you're a little obsessive about this place -- like we are -- you'll come back again ... and again).
You just can't beat getting off of the plane and then heading over to Duke's as fast as you can. It really hits you that you're in Hawaii: the music, the beach, the perfect weather. The food is excellent -- both at the Barefoot Bar and at the main restaurant itself. We've tried a variety of fish dishes as well as the BBQ ribs and (at the Barefoot Bar) the Hawaiian pizza with sweet chili sauce. Service is always friendly, and we've never felt rushed, even though there can be quite a wait to get in (if you don't have reservations)!
Make sure you plan ahead and request to sit as close to the beach as possible so that you can have views of the ocean and Diamond Head while you listen to the waves.