Manage custom posts columns, show custom taxonomies

functions.php

add_action("manage_posts_custom_column",  "artist_custom_columns");

function artist_custom_columns($column) {
	global $post;
	switch ($column) {
	
		case "performance":
		$_taxonomy = 'artist_performance';
		$terms = get_the_terms( $post_id, $_taxonomy );
		if ( !empty( $terms ) ) {
			$out = array();
			foreach ( $terms as $c )
				$out[] = esc_html(sanitize_term_field('name', $c->name, $c->term_id, 'category', 'display'));
			echo join( ', ', $out );
		}
		else {
			echo "n/a";
		}
		break;
		
		case "city":
		$custom = get_post_custom();
		if ($custom["_artist_city"]) {
			echo $custom["_artist_city"][0];
			echo " (";
			echo $custom["_artist_country"][0];
			echo ")";	
		} else {
			echo "n/a";
		}
		break;
		
		case "musiclabel":
		$custom = get_post_custom();
		if ($custom["_artist_label"]) {
			echo $custom["_artist_label"][0];	
		} else {
			echo "n/a";
		}
		break;
	
		case "slides_home":
		$custom = get_post_custom();
		if ($custom["_artist_slides_home"]) {
			echo $custom["_artist_slides_home"][0];	
		} else {
			echo "n/a";
		}
		break;
	
	
		case 'thumbnail':
		if ( has_post_thumbnail()) {
			the_post_thumbnail(array(100,100));
		} else {
			echo "n/a";
		}
		break;	
	}
}