No you still have a Primary email address which will always be the first @ntlworld.com account that you setup.
You can tell which is the Primary as it will be the only email address that when you go to
MyVirginmedia you can view or delete the other addresses, if you log into a Secondary Account you will only see that alias.
You can never delete the Primary alias either.
Also you are only allowed a maximum of 10 email addresses unlike the old system which allowed up to 15.