I DID go to Hawaii on my honeymoon.
We did 2 weeks, 2 islands.
Definitely rent a car, you can find a lot of neat places.
Maui was very calm and relaxing, stayed at the Renaissance Wailea:
http://marriott.com/property/propertypage/HNMRN
If you're on the island, drive the Hana Highway, it's awesome.
Second week was on the big island of Hawaii, stayed at the Hilton -
http://www.hiltonwaikoloavillage.com/index_flash.asp
Lots of kids, but the water park made up for it. They even have a freakin' tram! The volcanoes park is on this island, lots of fun as well.
Sorry can't help you on deals - we had a family friend who was a travel agent who got us ours.
There are island hopper flights like every hour, so no matter where you stay, you can check out every island.
Stacy
Stacy