The magento admin user can add custom variables which can be used in static blocks, the CMS section of the admin panel, and also in the transactional emails. To use these, we go into System > Custom Variables, and click add New Variable. You give it a code like store_city, and in the ‘name’ field put a description (yes, i know). Then you can set an html representation and a plain text representation of what you want the value to be.

Now when editing a CMS page or transactional email, we can do stuff like this:

<p>We are based in: {{CustomVar code="store_city"}}</p>

Nice and easy.