Poke
For poke fans, Umekes in Kona is the best. They share owners/cooks with the Kulena Rum Shack in Waikoloa Beach, so you can do a poke sampler and flight of rum there if you don't want to venture to Kona.
Pau Hauna Poke is also a local favorite for to-go and is located around the corner from Costco.