Summary

You can select one of your tax rates as the default for your site. This sets your chosen rate to the default value in the 'Include tax in this price' field when you create a new product.
Basically, it will save you a couple of clicks per product - but that's nice to have if you've got lots of data entry to do.

Requirements

commerce_tax

Install as usual, see http://drupal.org/documentation/install/modules-themes/modules-7 for further information.

Configuration

If you have exactly one tax rate on your site the module will select that and use it when it is installed.

If you have anything other than one tax rate, or should you add more later, you can configure from the config link on the Module page, or from the taxes page (admin/commerce/config/taxes/commerce_default_tax_rate )
Select your default rate and save.

NOTE

This does NOT affect items already in the system
It ONLY affects products added through pages such as node/add/product-display

This is currently a pretty trivial module, but maybe it will save you some time and help keep one of your users happy!

Commerce Default Tax Rate

Issues