Top 10 Password Crackers

http://www.oxid.it/cain.html
http://www.openwall.com/john/
http://freeworld.thc.org/thc-hydra/
http://www.aircrack-ng.org/
http://www.l0phtcrack.com/
http://airsnort.shmoo.com/
http://www.solarwinds.com/
http://www.foofus.net/fizzgig/pwdump/
http://project-rainbowcrack.com/
http://www.hoobie.net/brutus/

Top Packet Sniffers

http://www.wireshark.org/
http://www.kismetwireless.net/
http://www.tcpdump.org/
http://ettercap.sourceforge.net/
http://www.monkey.org/~dugsong/dsniff/
http://www.stumbler.net/
http://www.ntop.org/
http://etherape.sourceforge.net/
http://kismac.de/

Top Scanners

http://www.cirt.net/nikto2
http://www.parosproxy.org/index.shtml
http://www.wiretrip.net/rfp/
http://portswigger.net/suite/
http://www.acunetix.com/
http://www.nstalker.com/products
http://www.nessus.org/nessus/
http://www.gfi.com/lannetscan/
http://www-arc.com/sara/
http://www.qualys.com/