Suggestion for database driven navigation

[eluser]FuzzyJared[/eluser]
I am building a CMS, and have started working on integrating the content categories as links within the fronend of the site. My question is what would be the best way to set this up. I could get all the links from the controller and pass it to the the template section via a $data['nav'] = ''; But this would mean calling the same thing in every page function within the controller. I would much rather call the request from template file such as left_col.php.

Any suggestions would be helpfull