WP-Mix

By default WordPress displays a bunch of useless widgets in the Dashboard. Here is how to disable them.

Disable all of the default dashboard widgets

Add the following code to your functions.php file:

function remove_dashboard_widgets() {

	global $wp_meta_boxes;

	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_quick_press']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_incoming_links']);

	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_right_now']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_plugins']);

	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_drafts']);
	unset($wp_meta_boxes['dashboard']['normal']['core']['dashboard_recent_comments']);

	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_primary']);
	unset($wp_meta_boxes['dashboard']['side']['core']['dashboard_secondary']);

}
if (!current_user_can('manage_options')) {
	add_action('wp_dashboard_setup', 'remove_dashboard_widgets' );
}

Bada boom bada bing. Customize as needed to suit your goals.