H and I just got back from an anniversary trip to HI and I thought I'd share on here in case anyone is thinking of going to Oahu. I was a little nervous going there since it was my first trip to HI and everything I read was that it is the least "Hawaii-feeling" island since it is more commercial and has a lot of traffic so I was afraid it would just feel like I was in FL or something.
We stayed in Ko Olina, which is on the south and western part of the island, so away from the major hustle and bustle of Honolulu/Waikiki/etc. This part of the island was great, our condo was in an area with 4 lagoons so you had calm water to play in and snorkel but had waves crashing just beyond so the best of both worlds. The beach area was also quiet and we always found a nice spot with sun or shade and felt fine leaving our stuff on the beach to go up for lunch or walk to a resort next door for ice cream. The water was clear, the beaches were sandy and not rocky at all (H had said he's experienced rocky beaches in other areas of HI he's been to) so it was great. In the winter you can see whales from the condo lanai's although we were not there during whale season. Sadly we didn't see any dolphins either which I always enjoy.
Ko Olina was also nice for making day trips to other parts of the island and touristy stuff. We did the North Shore & Dole plantation, Pearl Harbor, Diamond Head & Hanauma Bay (awesome snorkeling place), and a brief stint at Waikiki beach (way too crowded and touristy for me). The only traffic issue was going from the airport to the condo because we arrived at rush hour and then heading to Pearl Harbor because we were in morning rush hour but otherwise it was fine.
Oahu was better than I expected with a nice mix of relaxation and activity. I think staying in Ko Olina was key to that because I would have felt differently had we stayed in Waikiki. I would definitely recommend the area although if I ever get back to HI I think I'd like to go to another island just to see what it is like, though I'd be happy to return to this one again.