Here, from Bruce Schneier, are 10 rules for protecting secure passwords. Passwords can be a bane of computer existence; there are just too many of them, though most of them are necessary and advisable.
That being so, a password management system can be a good thing. Yet Bruce (one of our foremost security management professionals) acknowledges he regularly breaks seven of these rules himself. But he also provides this advice on choosing secure passwords as atonement.