Hawaii has a special place in my heart. And Hawaii, to me, is the island of Oahu. This is the gateway to the Hawaiian Islands. Most everyone will come through Honolulu on their way to anywhere else in Hawaii. I would always recommend that people make the most of the stop and try to experience this island.
Oahu gets a bad rap because of their position. I've heard that people think it is too busy and they don't like being near a downtown area. Of course, many think Waikiki is too "touristy"...but what part of Hawaii isn't drawing tourists?
Waikiki Beach is a beautiful public beach with a great view of Diamond Head volcano. Yes, it is crowded. I am someone who enjoys people-watching so I don't mind the crowds so much! There are plenty of hotels in walking distance in a variety of price ranges. There is a ton of shopping, dining, and entertainment in this area as well. International Marketplace is a favorite destination for those nostalgic memories of Waikiki tourism. There are plenty of souvenirs and also quality products for sale there.
If you have some time to spend on the island, I would advise to take a drive around the whole island. The best places to stop are: Sandy Beach to watch the bodyboarders on the strong currents; Hanauma Bay for the beautiful snorkeling; Haleiwa to get shave ice at Matsumoto's; Dole Plantation just because you are there; and Pearl Harbor to remember that being in Hawaii was not always to tranquil and peaceful.
Enjoy the culture at the Polynesian Cultural Center or just trying restaurants off the beaten path. Read the local newspapers and talk to locals to find out the best places to check out while you are there. I cannot speak highly enough about Oahu and I wish I could take everyone there to show them how wonderful it can be.