What sites would you include in a "Useful Websites" directory?

I am composing a useful websites directory for the Residents of the building I work in. We have a small computer lab. I am including things like local resources, local events, research websites, education websites, nutritional websites, recipe websites, social networking sites, etc… (pretty much anything useful). What sites would you include? Do you have sites you use often and find to be quite useful?

TIA.