Form API #states with #default_value?
Your default value in the select element must be the array key of your values not the value it self.So i set an empty "value" and check for that.

That said i got this working like:

$form['wrap'] = array(
  '#type' =&gt; 'select',
  '#title' =&gt; t('How many item(s) do you wish to have wrapped?'),
  '#options' =&gt; array('--', '1', '2', '300', '400'),
  '#default_value' =&gt; 2,
);
$form['textarea'] = array(
  '#type' =&gt; 'textarea',
  '#title' =&gt; t('How many item(s) do you wish to have wrapped?'),
  '#states' =&gt; array(
    'visible' =&gt; array(
      ':input[name="wrap"]' =&gt; array('!value' =&gt; 0 ),
      ),
    ),
  );


In the example above my default value is 300.
The state visibility will work onload and onchange and will show the textarea only when the value is the empty value (0 => '--')