Magento – remove total excl tax in checkout, order invoice emails in magento2

The simplest answer is to double check the configuration option "Include Tax in Grand Total" found at System > Configuration > Sales > Tax > Orders, Invoices, Credit Memos Display Settings.

Source: http://www.magentocommerce.com/knowledge-base/entry/configuration-sales-tax-orders-invoices-credit-memos-display-settings

If this is correct and still an issue, reply back with some more detail (e.g. plugins that may influence tax calculation, custom theme in place?) and I will go look deeper. Hope this helps you or someone landing here in the future.

Found how to do this (programatically)....

Under {magento_base}/app/design/frontend/base/default/template/tax/checkout/

Edit file grandtotal.phtml
(I suggest you make a backup of the file just in case).

Find the line:

<?php if ($this->includeTax() && $this->getTotalExclTax()>=0):?>

Delete the subsequent lines:

<tr>
    <td style="<?php echo $this->getStyle() ?>" class="a-right" colspan="<?php echo $this->getColspan(); ?>">
        <strong><?php echo $this->helper('tax')->__('Grand Total Excl. Tax')?></strong>
    </td>
    <td style="<?php echo $this->getStyle() ?>" class="a-right">
        <strong><?php echo $this->helper('checkout')->formatPrice($this->getTotalExclTax()) ?></strong>
    </td>
</tr>

This change means it will now only show the tax inclusive line in the cart review.

Hope this helps someone else!