Should I use www in my url?

[jtmartin]

I have a word press blog that has been up for about a year. I have been very proud of the fact that I have achieved a Google page rank of 2 and that is probably going to go up as my blog has recently become very active with comments and back links.

I have always linked to my site with http://jtmartin.net, leaving out the www. I use the SEO Quake add on with Firefox. I did a Google search for my name and my blog is listed #1 but it is listed as http://www.jtmartin.net with a page rank of 0.

Should I be using the www when I create back links to my site or does it really matter?