Whats the best method for displaying different page layouts for a node based on taxonomy?
In D6, if you are displaying a full node page, you can use the preprocess_page() hook to select a different page template based upon that CCK field.  For example,

function mythemeormodule_preprocess_page(&amp;$vars) {

  $node=$vars['node'];

  switch ($node-&gt;field_i_am_interested_in[0]['value']) {
    case 'something':
    case 'anotherthing':
      $vars['template_file']='page-bytax-' . $node-&gt;field_i_am_interested_in[0]['value'];
      break;
  }

}


and then create page-bytax-something.tpl.php page-bytax-anotherthing.tpl.php etc with whatever page layout you want.

If though, you are really talking about how the node itself is laid out in the $content area of the page, you could do the same thing inside preprocess_node() and create node-bytax-FOO.tpl.php templates instead.

Also, depending on what kind of cck field you are looking at, you might need to change up the [0]['value'] part.

If D7, subtle changes apply :)