Preferred domain name

[web2008]

We have set preferred domain to: Display URLS as www.example.com in Google webmaster tools

Do we still nedd non-www to www redirection in .htacess?

[bill]

Yes, because not all other search engines will recognize that setting. Also, people linking to you may not realize your preference.

[lucy24]

Edit: Dang! Bill beat me by nine minutes.

Yes. Google is not the only search engine on the planet. And they themselves will expect to see a redirect.