Ok.... never been to Hawaii before and my wife wants to make a trip. Award travel, high/low season, fares/hotel cost, whatever aside:

(and if any of these questions are answered anywhere else, please send pointers!)

When is the best time to visit Hawaii for "bang-for-buck" ratio?
What should we intentionally miss..... what should we not miss?
Where should we go/stay? Where should we not go/stay??

My wife and I are into seeing and exploring. Not big on basking in the hottest weather available to get the richest tropi-tone tan we can find. We love gardens, we want to do the requisite helicopter tour, and as a photographer I want to see anything unusual or different (not sunsets and palm-trees, but I love ruins, temples, delapidated gorp, or anything interesting and different, and so-called bad weather isn't a stopper for me).

Pointers? Suggestions?
Thanks much,
D.