Doesn't really matter, use one or the other though, you don't want to use both because search engines will count it as two sites..
www or non-www is does not matter here. I think the best way to display link is the way others site link to you. If all other link to you as "www.yourdomain", mean that you should change your site to www. Because it the way search engine find your website fast.
Though it does't matter;a site without www is new trend over internet.So if you planning for new site then set it without www.
That is not the matter of best way to display my domain. Its the matter of canonical issue. If your website shown as http you can be find that your website also open with with www version ...this is the big problem. What i know is that search engine seems that as duplicate url. So I would preffer my website should open with www