I handy level. 5/0 police radio police scanner. Keyring. Also google maps for navigation if it didn't come preloaded. Posted from my iPhone/Mobile device
Weather Underground is pretty good for weather, and I like SailFlow for good wind predictions. iTides is pretty accurate for tidal predictions. Don't forget one of the flashlight apps... always comes in handy!
Tide app
Flashlight app for when you need light and only have your phone
Weather channel app
Shazam - which listens to song and tells you who plays it.