The second paragraph lists the pertinent biographical information as I would want it to appear in the "About the Contributors" section at the end of the journal. This way, the editors don't necessarily have to contact me about this.
On a practical level, I've found it easiest to keep the cover letters saved on my computer, adapting the heading and salutation for each journal. My philosophy with regard to cover letters is to keep them short and easy, and then submit to as many publications as possible. As with a job search, it's all about getting your work in front of the right pair of eyes.
