How can I get a block to display only on node view in Drupal 6
In the visibility textarea of your block, select PHP code and put the following:

&lt;?php
if (arg(0) == 'node' &amp;&amp; is_numeric(arg(1)) &amp;&amp; (arg(2) == '' || arg(2) == 'view')) {
  return TRUE;
} else {
  return FALSE;
}
?&gt;