TO WWW OR NOT?

To begin the conversation, let me first explain where the choice comes in. When a webmaster decides to use 301 Redirect and determines a source for a site, he or she must decide whether or not the site starts with the prefix “WWW” or not. For example:
Two versions of a site are created: www.example.com and example.com (without WWW). Both versions point to the same place, and for SEO purposes you would use a 301 redirect to combine both sites into one. But which site will bring more results? There are a variety of opinions on this subject. Below are some arguments for either opinion:
Reasons to use WWW:
When someone writes about your site using a Word document or email editing software, etc., listings that use WWW will automatically be recognized as websites. At this point, the listing turns into a live link when typed into a document or email. Potentially, people might click onto the site, generating more traffic! More importantly, if you have converted your Word document into a PDF file, and then posted it on a site, that post would contain a live link to your site, increasing the number of links that you have, and therefore overall enhancing your SEO. You could also create a live link in a document by using the http://, but since very few people ever do this, using WWW seems to make sense.
Reasons to skip WWW:
Some argue that the non-WWW version is more readable and user-friendly than WWW versions. Also, WordPress and other popular blogging sites default with a non-WWW version of the site.
I am starting to reconsider my opinion these days .When I type my own site into a document, I rarely use WWW. I type the URL and then change it to a hyperlink. Leaving out WWW allows a website’s address to sound more conversational. For example, when people talk about Amazon.com, they say just that, rather than calling it www.amazon.com.
I think this pro and con WWW conversation is open, and I’d like to hear your comments. Which version do you think is better for SEO?