Add Class to the Last Post in the Loop

This function adds a class to the last post in the WordPress loop. Using it lets you style the last post differently on the homepage or archive pages.

function last_post_class($classes){
	global $wp_query;
    
	if(($wp_query->current_post+1) == $wp_query->post_count) $classes[] = 'last';
	return $classes;
    
}
add_filter('post_class', 'last_post_class');

For more on WordPress template structure, see WordPress Template Hierarchy.