Even if you aren't blogging, your Wordpress-based site will have the benefit of Wordpress' built-in
SEO. Of course, regular updates to your site will help that.
In my opinion, a Wordpress-based site offers far more flexibility and, most likely, better
SEO features than a template will.
I got virtually no traffic to my site using a template when I first started out. Shortly after building a Wordpress-based site, my traffic began to increase. I never made a single "post."