How to use gmail.com as a mail archive, read all mail 
(including the mail addressed for gmail.com) on another machine 
and not cycle forwards (loop aliases).

Gmail does not allow filtering by Delivered-To header,
probably to force people to switch to gmail at once.
To overcome this, you need to set up your gmail filter
to forward every mail without "cc:forwarded" to your main mail machine. 
To make sure your remaining mail does not mysteriously disappear 
or lag for a long time set up a filter also for the files 
with "cc:forwarded" and let them be archived or starred.

After setting up .forward and .procmailrc files
in $HOME on your main mail machine all your mail
should land both at your main machine and at gmail
(it works under Postfix, but should also work with other mailers);
Here is the .forward file:

/home/your-user-id/your-maildir
"|IFS=' ' && exec /usr/bin/procmail -f- || exit 75 #your-user-id"

and the .procmailrc file:

# Most of the lines are unneeded, probably; 
# copied from http://www.erehwon.org/erehwon/procmailex.html
#
# Set path #
PATH=/bin:/usr/bin:/usr/local/bin:/opt/local/bin/:$HOME/bin:$HOME:
SENDMAIL=/usr/sbin/sendmail
SHELL=/bin/sh
# Set on when debugging #
#VERBOSE=on
VERBOSE=off
# Directory for storing procmail log and rc files
PMDIR=$HOME/.procmail
LOGFILE=$PMDIR/log
# Set environment variables #
UMASK=077
LOCKTIMEOUT=1024
TIMEOUT=960
SUSPEND=16
LINEBUF=4096

:0 h
* !^Delivered-To: your.name@gmail.com

    :0
    | (formail -i "CC: forwarded") \
    | $SENDMAIL -oi your.name@gmail.com