If you really want to see Hawaii, get off Oahu and head for Kauai (my personal favorite), Hawaii (the Big Island) and Mauai.
Of course in a week, you'd best just choose two destinations.
Kauai is the "Garden Island" very lush and green in the north and northeast, and amazingly arid in the south. The Na Pali coast in the north is an awesome trail that is not too challenging but lots of tourists. The Waimea canyon area in the south and southewest has some great areas to explore also, and if you head west from there you can find an awesome fairly quiet beach down a dirt road a few miles. (If you get serious about this let me know and I can talk to you more about it).
The Big island is amazing for its volcanic activity (and two earthquakes in the past 3 months). You can jump in the car and head to the Volcanoes National Park where you will find, of all things, a lush tropical rainforest. A few miles farther down and you are in the middle of a lavafield that stretches all the way to cliffs along the sea.
Mauai is beautiful but loaded with tourists. Haleakala (volcanic mountain) is pretty impressive and a small town, Hana, is beautiful. There's a nice drive around the northern end of the island. Mostly a hang out at the beach island. I never found much in the way of places to explore though I know they exist.
Anyway...HTH...let me know if you want to talk more in person. I can also recommend a few books depending on where you might want to go...
Ed
In case you were wondering, I kind of like Hawaii!
