To print the name of a node's content type, add these lines into your theme's node.tpl.php file.

Print the names for all types of nodes

<?php
print node_get_types('name', $node);
?>

Exclude a single content type's name from being printed

<?php
print $node->type != 'page' ? node_get_types('name', $node) : '';
?>

Exclude multiple content types' names from being printed

<?php
if (!in_array($node->type, array('story', 'page'))) { 
  print node_get_types('name', $node); 
}
?>

See http://api.drupal.org/api/function/node_get_types/ for more information.