smozz and I are in the midst of planning our every five year anniversary trip back to Hawaii. (We went there on our honeymoon and have gone every five years since.)
Unfortunately planning this trip seems much harder than five or ten years ago. The airlines have cut back on award availability. (Thank you Delta, but no, we don't want to travel on Wednesday if that is the only day you have available; Thank you Northwest, but no, we don't want to spend over 200k miles for two tickets (in First) to Hawaii.) Part of this was probably due to the fact that we are trying to save American miles for a trip to Australia for Worldcon in 2010 - five years ago we flew American and had no problems getting seats. So, it looks like we are going on Alaska Airlines and over-nighting in Seattle on both directions. But at least we got First and won't have to sleep on a plane and we get more American miles also.
We spend as little time on Oahu as possible. I'm sure it is nice. But Maui, Kauai, and TheBigIsland are all nicer. And Lanai and Molokai are more interesting / nice in a different way. And Oahu looks a lot like San Francisco when you get away from the beaches. And 12+ hours is just too long to fly to go to a San Francisco clone.
So we need to book inter-island flights. Now, we complicated matters a little by deciding to go Hawaii/TheBigIsland-Lanai-Maui (to get to Lanai you have to travel via Honolulu), but having Lanai in the middle has worked out in the past and it will be the weekend, so if connectivity isn't as good it won't matter. (I pretty much always get stuck doing some conference calls and checking email when I am on vacation. Given what I do, it is life.)
Last time we did this, we used a travel agent to book the inter-island flights. Unfortunately most travel agents want outrageous fees to do this now. ($49 to book a $110 flight? I don't think so.) So this is where ITASoftware airfare search comes in. It was helpful for HNL (Honolulu) - KOA (Kona, TheBigIsland) and OGG (Maui) - HNL. Unfortunately it didn't do too well for KOA - (HNL) - LNY (Lanai) and LNY - (HNL) - OGG. In one case I was able to create an (apparently) valid itinerary which it didn't list by booking two flights individually. This prompted me to try booking the two flights for another itinerary which it did list individually and I managed to get the airfare for $147 rather than the $300+ ITASoftware was quoting. Now I suspect part of this may have been web only airfares available on Hawaiian Airlines website. But, it just goes to show you that you may need to check the individual airline's websites to find the best deals.
We did manage to get 5 nights free on both TheBigIsland and Maui using Starwood points and for a few more points we were able to upgrade to Ocean View in both cases. So we just need to pay for a hotel in Lanai.