I went to Oahu in '02 to get hitched with the ol' lady. We did the tourist thing on that island for a week. We also brought our xc bikes and did a little bit of sight seeing and trail riding. Then hoofed it over to the big island for another week. We rode almost every day exploring places like Kiluea and Kona and such and it was a blast. We stayed in Hilo for a few days, found some trail, chased wild boars…that kinda stuff. Gotta say, I liked that island the most.
Then a year later we went back to Maui without bikes. Not as much fun but it also seemed like there wasn't really much riding there. Took the ferry over to Lanai(?) and explored around. That was a nice island for sure.
We're not big into water sports, so bringing bikes made sense for us. But I could definitely see just going there and renting bikes if you don't really plan on exploring off road and instead just touring around.