Default new users to no admin bar

I want to be able to default all new users created with the wp_login (register) box to have the user option:

Show Toolbar when viewing site

set to unchecked. I have the facility to then jump into wp-admin from within my website as and when required, but I don’t want the black bar always showing. Its all works perfectly fine if the option is unchecked, but any new user is checked by default which means until I can manually uncheck it I have a problem.

Thanks