Here are a few technology and information security related mailing-lists that I subscribe to in no particular order. Leave a comment if you think I missed one.

asterisk-users.lists.digium.com
beginners.perl.org
snort-users.lists.sourceforge.net
nessus.list.nessus.org
pauldotcom.mail.pauldotcom.com
samurai-devel.lists.sourceforge.net
ptk-forensics-mail.lists.sourceforge.net
gcfa.lists.sans.org
framework-hackers.spool.metasploit.com
framework.spool.metasploit.com
secureideas-base-user.lists.sourceforge.net
python-list.python.org
nexpose-users.lists.rapid7.com
winquisitor-beta.googlegroups.com
securitybsides.googlegroups.com
datarecoverycertification.googlegroups.com
full-disclosure.lists.grok.org.uk
scap_interest.ietf.org
cipp.news.infracritical.com
scadasec.news.infracritical.com
debian-security-announce.lists.debian.org
bugtraq.list-id.securityfocus.com
ietf.ietf.org
dfir.lists.sans.org
webappsec.list-id.securityfocus.com
sleuthkit-users.lists.sourceforge.net
vol-users.volatilesystems.com
emerging-sigs.emergingthreats.net