There is no simple answer to your question. Hawaii is a very diverse place. Each island has its own appeal, and very different things to do. If you want U.S. history, Pearl Harbor, Waikiki, and Diamond Head, you'll need to go to Oahu. If you want great beaches and an upscale pampered beach vacation, Haleakala, and the Road to Hana, you need to go to Maui. If you want laid-back peace and quiet in a less-crowded place, more beaches, the amazing Napali coastline, and more diverse weather, then you need to go to Kauai. If you want to see volcanoes erupting and wide open spaces, then the Big Island of Hawaii is the place to be. There are great Wyndham timeshares on each island. You need to make some choices about what sort of vacation you want, and go from there.
Dave