Weather...the all-important subject for us sailors. We could list many more, but here are some of the sites that we check everyday.
Weather Underground Conditions and Forecast at Logan - Nice, simple presentation of both current conditions and forecast
NOAA Current Conditions at Logan Airport - For the purists, just the facts from NOAA - Current Temp, Wind and Pressure
NOAA Coastal Marine Forecast - All NOAA's marine forecasts for Southern New England...be prepared to scroll.
Sailflow - Our not-too-secret vice, we honestly can't live without it. Not free, though. But want to know in a glance what it's blowing, where? Want breeze-focused forecast discussions written for sailors? One word: Sailflow.
IWindsurf - Good, free wind forecast tables from the Sailflow people.
Radar - Sure, sailors did ok for themselves for millenia without radar. But their life-expectancy is up these days, in no small part thanks to radar. Check it!
AccuWeather - General weather site, easy on the eyes, not too light on content