The ultimate email address regex
http://www.thebuzzmedia.com/the-ultimate-email-regular-expression/
http://fightingforalostcause.net/misc/2006/compare-email-regex.php
God-fucking-yes:
/^([\w\!\#$\%\&\'\*\+\-\/\=\?\^\`{\|\}\~]+\.)*[\w\!\#$\%\&\'\*\+\-\/\=\?\^\`{\|\}\~]+@((((([a-z0-9]{1}[a-z0-9\-]{0,62}[a-z0-9]{1})|[a-z])\.)+[a-z]{2,6})|(\d{1,3}\.){3}\d{1,3}(\:\d{1,5})?)$/iJust do it once, and get it right.
It's also a little more succinct than this one: http://www.ex-parrot.com/pdw/Mail-RFC822-Address.html