Make sure that you include relevant location information on your pages if that is pertinent to your business. For instance, while you might be happy to sell a widget to someone from Albuquerque, if the vast majority of your business comes from Ann Arbor, then make sure you include “Ann Arbor” along with your keywords and phrases.
If your business is more regional in nature, then make sure you include all of the cities, towns, and counties in the location description. That way someone searching for Webberville Widgets will be more likely to find your site.
Including dozens of locations on each of your pages could possibly clutter up your site, but there are ways to do it where you can minimize the impact. Try placing this information “below the fold” – that is at the very bottom of the page where it usually says “Web Design By ….” and the color changes from the color used in the content area to the background color of the page. Who cares if it is cluttered down below – very few people will ever scroll down to see it, but the search engines will take notice, and that after all, is the goal!