Basic forecast links
The links below are your basic 5-day weather forecast. I like the National Weather Service the best due to accuracy, and the abundance of data from 5-day forecast icons to complex charts and discussions. It is also the one and only official issuer of Watches/Warnings/Advisories.
The National Weather Service (weather.gov) is the official issuer of Watches/Warnings etc. They provide a point and click forecast for anywhere in the country(You can even get a forecast for your front yard).
The Weather Channel (weather.com) provides the quintessential sun/rain, hot/cold forecast. A good out-the-door-in-a-hurry resource. However, take their storm forecasts with a grain of salt-they tend to hype things.
WeatherUnderground (weatherunderground.com) is one of my personal favorites for reading about the weather. They provide the basic 5 day forecast along with current conditions at the nearest airport, lunar and tide cycles, and a whole lot more. It still earns the distinction of user-friendly so don't worry about getting lost in information you're not going to use. Also on WeatherUnderground is a fascinating blog by Jeff Masters I enjoy a lot.