I just finished reading a book on this very topic, and recommend it highly. _Perfect Passwords_ by Mark Burnett, available at: http://www.amazon.com/Perfect-P

I just finished reading a book on this very topic, and recommend it highly. _Perfect Passwords_ by Mark Burnett, available at: http://www.amazon.com/Perfect-Passwords-Selection-Protection-Authentication/dp/1597490415/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1233437215&sr=8-1 http://www.amazon.com/Perfect-Passwords-Selection-Protection... It's full of great analysis, as well as a fun table of the 500 worst passwords of all time. :) (Note: I am not connected with the publisher or author in any way.)