I have been trying to find a ListServ software package to service our opt-in email list. We need software that will allow for personalization of each message. We don't allow our subscribers to directly change/unsubscribe their information, I take care of that manually. All I really need is a bulk email program to take care of a list that is split into four different ways that the weekly message is sent (text only, html, text + attachment, text + 2 attachments).

Can anyone recommend a good, configurable bulk email/listserv software package?

Thanks in advance.