Would you buy your password from an 11-year old girl? I would, and maybe you should, too. Mira Modi, an 11-year old New Yorker, has very very cool service called Diceware. Using a technique developed by Arnold Reinhold, Mira uses dice to come up with a unique 6 word passphrase, which she will send to you in the US Mail. Her fee is two bucks.
Understanding that passwords are cracked by cyber-criminals one of two ways, either from a stolen list of known cracked passwords (rainbow tables), or using a computer botnet and software to try every possible combination (brute force). Without going into the math, longer but simpler to remember passphrases beat shorter complex passwords that are harder to remember.
An xkcd comic on her home page explains why longer passwords are better this way:
So if you want some professional help getting a truly uncrackable password, you would want to give Mira’s password site a try. Her simple three page site explains it all, and is worth the trip even if you are not going to buy.