Technically, the template can be called almost anything (see these two lists for names you should not use; these are special file names WordPress reserves for specific purposes). However, using a standard name for your template will make it easier to change your blog’s theme or distribute your theme and template to the WordPress community. It’s also possible to display a large archive index using one of the all-purpose templates (like index.php or category.php) and the is_page function, but again, taking advantage of the theme system’s modularity makes it easier for others (and for you!) to edit your template later.