My wife grew up there, so we go to visit her family, but always manage to fit in a week or two not visiting the family.
Kona is the premium Hawai'ian coffee, but the last year or two, the premium coffee from Moloka'i has been better, in my opinion. I usually order from--
and recommend the Malulani Estate coffee, the Hawai'ian Espresso, and if you like flavored coffees the Moloka'i Island Princess which has Tahitian vanilla. If you go, stop at the plantation, take the tour, and order a Mocha Mama from the coffee bar.
Even with shipping to the mainland (not that I live on the mainland, since Manhattan is also an island, after all), it's cheaper than Kona, too.