This sets standard settings on theme activation

WP - Standard settings

/*
* Get standard settings upon installation
*/
function gr_set_defaults(){
  $o = array(
		'avatar_default'               => 'blank',
		'avatar_rating'                => 'G',
		'category_base'                => '',
		'comment_max_links'            => 0,
		'comment_whitelist'            => 0,
		'close_comments_for_old_posts' => 1,
		'close_comments_days_old'      => 90,
		'page_comments'                => 1,
		'comments_per_page'            => 10,
		'default_comments_page'        => 'newest',
		'comment_order'                => 'asc',
		'blogdescription'              => '',
		'date_format'                  => 'j. F Y',
		'date_format_custom'           => 'j. F Y',
		'time_format'                  => 'H:i',
		'time_format_custom'           => 'H:i',
		'default_ping_status'          => 'closed',
		'default_pingback_flag'        => 1,
		'default_post_edit_rows'       => 50,
		'links_updated_date_format'    => 'j. F Y, H:i',
		'permalink_structure'          => '/%postname%/',
		'timezone_string'              => 'Europe/Copenhagen',
		'use_smilies'                  => 0,
	);
	foreach ( $o as $k => $v ) {
		update_option($k, $v);
	}
	wp_update_term(1, 'category', array(
		'name' => __('News','green'),
		'slug' => 'news'
	));
	wp_delete_post(1, TRUE);
	wp_delete_comment(1);
	return;
}
add_action( 'after_switch_theme', 'gr_set_defaults' );