I had originally setup the permalink to be month and name instead of the default of the id number.  That made a lot of sense to me.  However, I read that for SEO reasons you want to display the postname so I changed it to a custom structure of /%postname%/.

I recently read that you want to include the category name.  For SEO reasons, this makes all of your URL have a common category subfolder that provides richer keywords.  So, I am now using /%category%/%postname%/.