I've seen variations on this problem while reading through the forum posts.  However, I think I see a common thread and no one seems to have an answer for this issue.  I have done some testing and found out that we can get our new registered users to receive their notification emails when we set up the registration type as Private or Verified.  However, new users do not receive their notification emails when the registration type is Public.  The administrator account DOES receive the emails.  I know that this has nothing to do with the SMTP server settings because we have emails flying all over the place with other notification types, and with the other registration types as noted earlier.  It's just when we set the site up with Public registration.  Am I missing a setting that states whether users should or shouldn't be notified when the registration type is public?