What does a secure password look like?
Great advice from Bruce Schneier on password security that looks at how passwords are cracked to determine how they should be made secure:
So if you want your password to be hard to guess, you should choose something not on any of the root or appendage lists. You should mix upper and lowercase in the middle of your root. You should add numbers and symbols in the middle of your root, not as common substitutions. Or drop your appendage in the middle of your root. Or use two roots with an appendage in the middle.
Definitely worth reading the whole thing.