Remove tax line item on checkout page
Might be a bit late on this one, but there doesn't seem to be a posted solution online. You can remove the tax line using the below.

In your template.php file use the below, this should hide it from your order confirmation email as well. I haven't noticed any problems from this modification, but ymmv. The variation from the standard code is: $rows = array_splice($rows, 2);

function THEME_commerce_price_formatted_components($variables) {
  // Add the CSS styling to the table.
  drupal_add_css(drupal_get_path('module', 'commerce_price') . '/theme/commerce_price.theme.css');

  // Build table rows out of the components.
  $rows = array();

  foreach ($variables['components'] as $name =&gt; $component) {
    $rows[] = array(
      'data' =&gt; array(
        array(
          'data' =&gt; $component['title'],
          'class' =&gt; array('component-title'),
        ),
        array(
          'data' =&gt; $component['formatted_price'],
          'class' =&gt; array('component-total'),
        ),
      ),
      'class' =&gt; array(drupal_html_class('component-type-' . $name)),
    );
  }

  $rows = array_splice($rows, 2);

  return theme('table', array('rows' =&gt; $rows, 'attributes' =&gt; array('class' =&gt; array('commerce-price-formatted-components'))));
}