My definite no's: L&L and Zippy's. Eh, nothing to memorable except remember to go somewhere else. The L&Ls on the Mainland are even worse. And if you are on the Mainland, don't go to The Loft restaurants in the Torrance/South Bay area - there are better places down the street.
When on O'ahu, definitely hit up Grace's or Rainbow Drive Inn.
On Maui, I avoid Aloha Mixed Plate. Prices keep rising and portions getting smaller. I guess they get away with it since it is in a touristy area. I prefer Mama San's in Pukalani, Cupie's Drive Inn in Kahului, and when I get the chance, Ichiban in Wailuku.
On the Big Island, my faves in Hilo are Cafe 100 and Verna's. If no can, no can. If can, Verna's....