The wife and I just got back from Oahu for our honeymoon. we stayed at Turtle Bay for a week. And all i can say is the north shore is AMAZING!!! Beautiful, chill, quiet, and the locals are some of the nicest people we've ever meet.
If you are more into nightlife, clubs and whatnot. Honolulu or Waikiki night be for you. We are more on the mellow side.
But North Shore has tons of stuff to do, surfing, snorkeling, scuba, kayak, all kinds of good stuff.
Our trip ran us just under $4,000 for hotel, flight, and rental car. We flew out of San Francisco, not sure if itll be different from where you are.