the_content not working

Without wanting to be rude: You should start by reading some tutorials on PHP.

This is (most probably) what you want to do in your question:

<?php
if ('bags' == get_post_type())
    the_post_thumbnail();
elseif ('books' == get_post_type()) {
    the_content('editor');
    the_post_thumbnail();
}
?>

Is this working (as you want it to)?