Been over a decade but probably have to go with Maui/Oahu. If you're gonna go to Hawaii in general it should be a long trip, the flight does suck, helps to not have to get back on a plane right away if going from the east coast. Enjoyed both islands immensely, very different experiences. Spent more time on hotel property in Oahu, but also enjoyed Waikiki, Lanikai is a great beach, north shore is fun and beautiful. Maui has more natural beauty and I found myself being more adventurous, cliff jumping off waterfalls along the road to Hana--I was intimidated by the ~35 foot fall with no lifeguards or professional presence around until I saw a mother and her young daughter do it together, then my ego kicked in and said I would be a giant wuss for not doing it, ironically my wife sustained a pretty painful injury doing it after me); biking down Haleakala after watching the sun rise at 10000 feet, to encountering a shark in person while snorkeling off Molokini. Parasailed courtesy of some odd German guy, had been referred via word of mouth as he didn't advertise his services because he supposedly went higher than is legally allowed. Fun but over with pretty quickly. Also some of the best seafood I've found anywhere. Odd thing I remember, on a couple occasions in two weeks we ate chain/fast food and I found the menus to be very different from the mainland versions of those same establishments.
Dark horse unmentioned in this thread--Catalina. Enjoyable visit to a place that was like its own little world, but don't need to do it for more than a few days. Never did find the wine mixer though.