Setting Preferred domain www vs non WWW which is best ?

There may be question on setting up a preferred domain and which one would be better for SEO. However I would say both of them is okay and you could use anyone, however be sure you make a redirect.

What I mean is if you choose www then redirect all your non www to www, this will help you pass a link juice.

I have been working for my new site that helps in free image hosting in the internet and I have implemented all my tricks there as well.

You need to pass a 301 redirect in order for a proper SEO. It can be done by adding following code in your .htaccess file.

RewriteEngine On
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]

The code above will redirect every non wwws to www.

How to Choose ?

Usually I check which of these two are more indexed and I go with the one which is highly indexed.

For my case, in my affordable website design packages site,  I checked and found that my home page was ranked for WWW, so I choosed www as preferred domain in Google webmaster tools, added a htaccess code to redirect all my non wwws to the wwws.