What's a website without links, right? Might as well give out a few I like.
 
United States Weather Pages A graphical map of the United States displaying weather advisories
Storm Prediction Center Located in Norman, OK - in charge of forecasting severe weather
WeatherTap Excellent weather site - requires payment though
Intellicast Just like WeatherTap, however free (and not updated as quickly)
Unisys Computer Model Outputs, Satellite Maps, Data Map Plots, etc
Eastern US Weather Forum Chat or read others opinions on the weather (includes pro mets as well)