Thanks Mark!
I've disabled these services as well as courier with update-rc.d like this:
Code:
update-rc.d -f amavis remove
update-rc.d -f spamassassin remove
update-rc.d -f clamav-daemon remove
update-rc.d -f clamav-freshclam remove
update-rc.d -f courier-authdaemon remove
update-rc.d -f courier-imap remove
update-rc.d -f courier-imap-ssl remove
update-rc.d -f courier-pop remove
update-rc.d -f courier-pop-ssl remove
It seems to have done the trick. My memory usage is down to 168M now.
Just one more question.
How do I re-enable these services, if I ever decide to provide e-mail services locally?