Interesing facts on Password strength: length beats complexity
Thanks to Kate Gregory for the reference.
This article: http://www.avertlabs.com/research/blog/index.php/2007/11/02/password-policy-length-vs-complexity/ points out that increasing password length helps more than increasing password complexity in terms of security.
I've been using pass phrases for several years. Most of my passwords are several word, which means they may be as long as 400 characters. And yet, they are easy for me to remember, and I don't have to write them down on some little sticky note that can be compromised.