If you wanted categories_id 1 to be rows and all others columns and you were set to columns and change the IF to read:

PHP Code:
<?php
/**
* load the list_box_content template to display the products
*/
if ($current_category_id != && PRODUCT_LISTING_LAYOUT_STYLE == 'columns') {
require(
$template->get_template_dir('tpl_columnar_display.php',DIR_W S_TEMPLATE$current_page_base,'common'). '/tpl_columnar_display.php');
} else {
// (PRODUCT_LISTING_LAYOUT_STYLE == 'rows')
require($template->get_template_dir('tpl_tabular_display.php',DIR_WS _TEMPLATE$current_page_base,'common'). '/tpl_tabular_display.php');
}
?>