What is the best way of archiving incoming emails on server?

I have a central email server (Ubuntu 8.04 amd64), running

- I would like to know of the 'best and recommended' method for archiving all incoming email received by the system.

I have seen two methods, both of which are proving to be unsatisfactory., using postfix, aliases or procmail

1) Create an 'archive_username' account for each user which receives a copy of each email received by user.
This is robust and is know to work, but has additional overhead to configure.

2) Use global procmail delivery rules - PREFERED
This 'sort-of' works, but procmail is giving me errors on some email messages, which are then bounced.

The solution that I would like:
- Every user receives their email in a Maildir directory in their own home account.
- A copy of every email is stored elsewhere (eg. /var/backup/mail_archive) either in
  a per user Maildir directory, or a global Maildir directory.
- As robust as possible (eg. a segfault in procmail currently causes mail not to be delivered to
  users).. so getting postfix to make the copy (rather than procmail) is probably preferred.