My wife and I went in 2009 for our 35th anniversary. We stayed at a time share in Waikiki for a week. That was a gift from my sister in law.
We also had a rental car, so take that into account from what I post.
USS Arizona. Get there early. We were there a 0600 and got on the first boat out to the memorial. One thing found interesting is that there were a lot of Japanese tourists that went there. By the time we came back, about 0800, the line was about three hours long.
Pacific Aviation Museum. It was only one hanger a few years ago, but I think it's grown. I had a great time there.
USS Missouri. Worth the trip, the guides are volunteers and some are better than others.
Ford Island itself. There are a lot of things to see and I think there is an organized tour, but we didn't do it. Probably a mistake since I doubt I'll get back.
The Punch Bowl. Another must see. Plan on a couple of hours.
Check the hours on the Fort_DeRussy museum. It was never open when I could go.
There is a Polynesian Village theme park (sort of) on the North Shore. It's run by Brigham Young University. It's a whole day affair if you decide to go, with a Luau at night. It's staffed (mostly) by young people from the various islands who will tell you about historic life on the various islands.
You'll see a few indoor firing ranges in Waikiki. As bad as Hawaii gun laws are, Japans are far worse and they draw a lot of tourists to them. I think some of them feature full automatic firearms, but I did nothing more than look at the signs.
The beaches are gorgeous. I'm not really a beach guy, but I did a lot of walking up and down the beaches. The ocean and ahem, other scenery, are incredible.
We never got to Diamond Head, another thing if we ever do get back.
A couple of practical things. We were advised to stay to tourist areas. Honolulu is not much different than any other big city. There is crime, there are people who will prey on tourists, there are poor people. Stay to the touristy areas and you'll be fine. Lots of cops in Waikiki to keep the tourists safe.
Lots of homeless people there too. They aren't supposed to camp on the beaches, but they seem to do it without being bothered.
We used a book called "Oahu Revealed", written by a guy that lives there. Very valuable in finding good deals in restaurants and other things. I found some really good and not too expensive places to have breakfast within walking distance of where we were staying.
There's also a huge Sunday morning flea market if you're into that sort of thing. It's near Pearl Harbor, so it's not walking distance.
It's pretty expensive, but you probably know that already. I'd go back one time if I could, just to catch the things that we missed.
One last thing. If you buy a Hawaiian shirt, wear it untucked.
