We've stayed on Oahu, because that's where the most "touristy" things are. Any hotel in Honolulu (name brand) will probably be fine.
Make Pearl Harbor a must see. There is also a neat place on the Windward side called the Polynesian Culture Center. It's a great place where you travel from island to island seeing shows about all the Polynesian cultures. Very entertaining! At night they have a HUGE show...Hula, fire, the works!
Take a drive around Oahu, there is the Dole pineapple plantation where you get get the Dole Whip (pineapple) with a fresh spear of pineapple. YUM!!!
Get Hawaiian Shave Ice in a little town called Halieewa (sp?). It's an old surfer's town. Great atmosphere.
Go snorkeling at Shark's Cove (watch out for the sharks). Go to Hanauma Bay and feed the fish. It's amazing, you can snorkel there, or just walk into the water. The fish come right up to you!
If you want to see an active volcano, take a plane to the Big Island (Hawaii). There, you can go to the top of Kilauhea (sp?) It's an active volcano, but is erupting from underneath. We looked right down into the crater. Awesome! On that island there is also a black sand beach where there are loads of Sea turtles sunning themselves and feeding. Again, awesome!
Take the whole two weeks, you won't be disappointed.
PM me if you have specific questions. My Mom used to live there.