I probably am pretty dumb for replying to a post that's quite a few months behind, but....whatev, I guess.
My favorite parts about Super Mario Sunshine were the secret areas with the remix of the original Mario theme...snapping fingers and everything. I especially loved the area where you have to relay on the Pinatas to give you the old heave ho from platform to platform. ...How did they get there in the first place, I wonder? Ah well.
My second favorite part? Spraying/jumping on Toadsworth and hear him going "Yaada-bla-bla-bla-bla!!" Cracks me up everytime.
I also liked seeing Mario sport a Hawaiian shirt and sunglasses. Though the Hawaiian shirt did look pretty odd on him...