A friend who is heading to Hawaii soon knew I'd been to the Big Island and emailed for any suggestions I might have. I had plenty (you can see them here), but the one I was perhaps most enthusiastic about was Hana Hou in Naalehu.
It claims to be the southern-most restaurant in the U.S., and, if I'm reading the map correctly, they're absolutely spot-on with that assertion. In any case, they make the best coconut cream pie I've ever eaten, and their macadamia nut cream pie ("mac nut pie" in local parlance) was if not life-changing at least vacation-enhancing.
Read more About Hana Hou.