Worthy websites

Here's a list of websites taken from the McMath Top 10 slips.
www.answers.com
www.onemorelevel.com
www.cbc.ca
www.**nasa**.gov
www.discoveryhealth.ca
www.harrypotter.com
www.aircraftresourcecenter.com
www.addictinggames.comwww.mathfacts.com
www.teensrc.ca
www.flickr.com
Have you ever checked them out?
What do you think?
Are there better ones out there that serve the same purpose?

How do websites improve or alter your reading skills?
Do you prefer reading online or from books?