Lets assume you've got a client (relax, this is the last hypothetical client!) who's an "open source media designer" and would like a very clean and sparse home page. So sparse, they'd like only a list of the titles of the top, most current posts from two specific categories to appear. (In an ideal world, a decision like this would ensure their site's awesome design could sink in on the user before bombarding them with content.)
They'd of course like it to be slick. When you click on the title for a post, it loads in through AJAX, nice n' smooth. There's no reloading over to a single content page.
To get started on this request, we'll have to reference what we understand of the Template Hierarchy and custom loops. We'll create a
home.php template page that will become the default home page which only displays the five most recent posts for the "WordPress Design" and "Inkscape Illustration" categories. Sounds straightforward enough, so let's get started.