Where to get great shots???

I am returning to Kauai for my 3rd visit in June, and wonder what locations people have found for those oh-so-great shots?  I've enjoyed visiting Waimea canyon (though haven't gotten a great shot yet).  Poi'pu beach was great as well ... hope to get back there this year.

Where else should I visit?  We're on the island for 5 days, so we've got lots of time to explore this somewhat familiar island!

The lighthouse on the north shore was a great visit last time, but I'm not sure if I need more from there.

Is the National Gardens a must do?  Haven't done that, yet.

One off-topic question, as well ... I'm a woodworker, and would like to buy some Koa to bring home.  Is there a lumberyard anyone can recommend, beyond the Koa Store, which is very convenient, and, uh, pricey?