When ever I receive an email from the mailing lists there are a few things that always make me do a double take.
The to field is to Me specifically rather than to the name of the mailing list. So I always have to check if this is a private email or a group email. The from in the mailing list is set as I would expect. In smtp terms (if I understand correctly) I would like the To field to be the mailing list address, the Delivered-To address to be me. And the From address to be the person sending the email, and the Reply-To to be the mailing list.
At the beginning of each email is a 'from: username' which is redundant since it is in the From of the email