I think the following safety equipment should be carried on any trip of signifigant distance:
Hand Held VHF Radio
Cell Phone
Whistle
Flares
Strobe
Colored Glow sticks or lights, big flashlight for lighting up mainsail
GPS
Air Horn
Knife
Tow Rope
medical kit
I think it's better to be safe than sorry, especially when something as simple as a pin coming out can change your situation from fun sailing to life threatening.