Depends on your speed. If you want to be in a city and have night life go to Honolulu. If you want a more peaceful experience but still touristy (and great for kids) go to Maui. If you want to spend time with your SO w/o kids and just want the raw beauty go to Kauai. I have been to the last two, and will probably not go to the Honolulu because neither my wife nor I like that kind of vacation. We have SF right next door. We can do the same thigns there (but without the volcanos)
We have been to Maui twice and are going back to Kauai for the second time this fall (Sept), so you can see where our choices are.
A few things worth mentioning. After about 9:00PM in Kauai,
everything except Safeway closes. So if you want to do more than watch the waves crash in, don't go to Kauai. It is beautiful and *WE* love it, but that kind of vacation is not for everybody.
Maui has in my experience better snokerling and Kauai. More coral, more fish.
Seth is probably right. Ask ChrisK(Prime screen name), he lives on one of the islands.
If you don't want to go that rout, do your self a favor and get one of these books:
http://www.amazon.com/exec/obidos/t...102-2891966-2736118?v=glance&s=books&n=507846
They have one for Kauai and the Big Island. They are great books. I think the best. We have lent both of ours out to people and they love them. You will see a dozen people at least with these books when you go there, but that is for a reason. They are great, and written by people who live there.
Good luck, LMK if you have more questions