While Drupal for Facebook module seems to be the best and most flexible option out there for integrating Facebook with your Drupal website, one thing about it that ticks me off is its forced single sign-on approach between Facebook and Drupal.
It’s easy to get the impression that modern site building using tools such as Drupal, Wordpress or Joomla is just a process of installing them plus a couple of modules. Then click away in the UI-configuration and the site is ready.