One of Art's also-retired co-workers from the U.S.E.P.A. in Chicago is here on Oahu. We'll be taking them around tomorrow. They've been here before, but haven't seen the Iolani Palace so that's where we'll take them. We're considering the
Plantation Village in Waipahu as well. That's where they have all the different types of sugar plantation houses that were built for the different cultures that arrived in Hawaii to work the fields.
So what else is there on Oahu?
Here's my list for anybody coming to Oahu (Grouped by location, but you know what I said about my sense of direction):
Waikiki:Diamond Head (You can walk up, if you like hiking in the hot sun.)
Waikiki (International Marketplace, the beach, Duke Kahanamoku statue)
Honolulu Zoo (can't compare with the mainland zoos, but they have
a, as in one lion now)
Waikiki Aquarium (I've not been here since I was little, and that's a long time ago.)
Ala Moana Shopping Center (You can walk there, if you like walking in the hot sun.)
Honolulu:Doris Duke's Shangrila home (Discover how the richest of the rich used to live. They probably still do, but I don't know where they are.)
Honolulu Academy of Arts
Punchbowl Cemetery
Tantalus Look-Out (You can see a whole lot of the leeward side of the island from up there.)
Iolani Palace (It's been renovated beautifully and is the only royal palace in the U.S. last time I checked.)
State Capital (It's sort of shaped like a volcano.)
King Kamehameha statue
Mission Houses Museum
Chinatown (I haven't been there in ages.)
Bishop Museum (It's been recently renovated.)

Foster Gardens (It's compact, but I really like that place. It's shaded.)
Discovery Center in Kakaako (We're taking our granddaughter there next time they come. Everybody tells me it's great for kids. Not cheap, but fun they say. Hey, this is Hawaii. Not a lot of cheap stuff here. OK... there is the beach... That's cheap, but how long can you sit there?)
The Windward Side (I call it the Other Side):Sea Life Park (can't compare with the mainland aquariums)
Pali Look-Out (You go there for the WIND and imagining how awful it must have been when so many people died being pushed over the cliff by the conquering warriors of King Kamehameha who unified the islands.)
Hanauma Bay (Be mindful of the hours and limited parking. I remember when Tif was little and freaked out by all the big fishes swarming around her.)
Byodo-In Temple (They filmed part of Lost there.)
Polynesian Cultural Center (This place could take up your whole day. It's not cheap, but gives you a wonderful overview of the Polynesian cultures.)
Blow Hole
Endless beaches
North Shore:Haleiwa (Matsumoto's does NOT have the best shave ice on the island.)
Endless beaches
Pearl Harbor:Arizona MemorialBattleship Missouri Memorial
Bowfin Submarine Museum (never been there, but I have a discount coupon)

Aloha Stadium Swap Meet (Wed, Sat, Sun: Tif's favorite place and the most reasonable place to buy tourist souvenirs--Oh, and you have to like walking in the hot sun.)
Middle of the Island:Dole Plantation (check out different kinds of pineapples and ride the little train, maybe walk the maze if you like walking in hot sun)
Wahiawa Botanical Gardens (need bug spray)
Leeward:Plantation VillageFor tourists from Japan: Waikele Discount Mall (especially the Coach outlet and the best shave ice on the island..so far)

Hitachi Tree (Moanalua Gardens)
Did I miss something important?
Don't forget to always pack your sun screen because there's a lot of sun here. I write this as I listen to the pouring rain outside my window.