My Recommendations:
Oahu
Hike up Diamond Head
Visit the Honolulu Zoo
Watch the lighting of the Tiki tourches in Waikiki
Visit the USS Arizona Memorial at Pearl Harbor
Tour the USS Missouri at Pearl Harbor. You can purchase a flag that has flown over it.
Tour the submarine USS Bowfin at Pearl Harbor
Shop at the swap meet at Aloha Stadium. You will find the best prices on your Hawaiian shirt and other merchandise there.
Go to the top of Aloha Tower, shop, and dine at the Aloha Tower Marketplace.
Visit the Polynesian Cultural Center
Tour the Dole Pineapple Plantation
Snorkel at Sharks Cove
Visit Maunalua Bay Beach Park
Visit Koko Crater Botanical Garden
Go to Sunset On the Beach for free Hawaiian entertainment and a free movie. There are food vendors there as well.
Eat and shop at the International Market.
Enjoy a day at the beach.
Tour the island on the Bus. It’s one of the best ways to see the island.
Here is an excellent restaurant guide.
specials/bestrestaurants07/

Pose for photos in front of the Duke Kahanamoku Statute. There is a live web cam there, so you can call one of your friends that are on the net, give them the address, and wave to them live.
/multimed/waikiki.asp
……

Kauai;
Visit Waimea Canyon
/parks/kauai/index.cfm?park_id=4

Visit Kilauea Point National Wildlife Refuge
/Kilauea Point Lighthouse
/profiles/index.cfm?id=12530

Visit the The Hanalei Valley
/virtual_kauai_tour/hanalei+
princeville+kilauea/Hanalei_Lookout/

Tour The Napali Coast
/virtual_kauai_tour/hanapepe
+waimea+kekaha/Napali_Boat_Tours/

Aloha!

Here are my suggestions:

OAHU
*Hike Diamond Head
*Take a surfing lesson
*Take a catamaran ride off Waikiki Beach
*Visit the Waikiki Aquarium (they have Hawaiian monk seals there — endangered species and VERY cute!)
*Pearl Harbor/USS Arizona Memorial
*Snorkel at Hanauma Bay
*Have shave ice at Aoki’s or Matsumoto’s on the North Shore (rent a car and drive around the island)
*Have dinner or drinks at Duke’s in the Outrigger Waikiki Hotel

KAUAI
*Zip line! (http://www.adventureinhawaii.com/kauai_zipline.htm). I have only done this through Kauai Backcountry Adventures in Hanamaulu, but the one I’ve given you the link for is in Princeville, so it might be easier for you.
*See Waimea Canyon
*Kayak Wailua river

Make sure to save some time for just relaxing…lying on the beach or whatever. This is your honeymoon and you should enjoy it! Don’t spend the whole week running from one activity to the next. You’ll enjoy it more if you’re well-rested and you spend time just hanging out together.

I LOVE HAWAII
but here are really fun things to do- Helicopter tours, snorkeling, hiking, outrigger canoing, cliff diving on the north shore of Oahu and go to volcano national park and on the early morning rainbow hikes!!!!!

There are so many great things to do in both locations. Helicopter tours, snorkling, hiking, outrigger canoing, cliff diving on the north shore of Oahu.