In my opinion, the Arizona Monument is a must stop on a visit to Honolulu. The again I am a bit of history buff. Still I think most people will find the trip here quite moving. Tickets are free on a first come first serve basis. So it is recommended that you arrive early. You will pick up your ticket from the front desk and be assigned a time to begin the tour. The later in the day the longer the waits usually until tickets run out for the day.
After you begin the tour you see a short film on Pearl Harbor and World War II. After the film you board a boat to ride out to the memorial. The memorial is floating in the harbor above where the Arizona sank during the attack on Pearl Harbor. You can actually see parts of the memorial in the water. On the memorial itself there is a well listing all of those who died on the Arizona. When we visited there was an Arizona survivor there and it was quite interesting and moving speaking to him.
In addition the memorials itself, there are a number of other interesting sites to see in the area. In the waiting area there is a small museum with pictures and items from World War II. Nearby, for a fee, you can tour the USS Missouri a battleship from World War II and a World War II submarine. Both of these are quite interesting and worth visiting while you are in the area. The Missouri is where the Japanese surrendered to officially end World War II. So you can tour memorials to where World War II started for and ended for the United States.