I was born and raised in Hawaii so I can probably help. Need to know what all you want to 'do'. O'ahu is the main island as far as Waikiki, Arizona Memorial, beaches for swimming and/or surfing, and other touristy stuff. It pretty much is open 24/7. The other islands (Kauai, Maui, Hawaii - the big island) are more scenic - so lots of hiking and driving but the towns tend to close down fairly early in the evening except at the larger hotels.
As for hotels, if you stay in O'ahu anyone with a good special will probably be okay. There are some pretty pricey ones so you have to research it. Tell me what you've planned so far and I'll give you my opinion
