From http://xkcd.com/936/
However, howsecureismypassword.net says that correcthorsebatterystaple would be cracked "instantly" whereas Kapersky's password checker says, that it would take 892 centuries to crack it. Obviously howsecureismypassword.net is aware of that comic and put that password in its database.
Also I would suggest not to build a normal sentence with "subject verb object adjective", which would make it easier for a computer algorithm to successfully try. Just put 4 or more random words like the comic suggests and try to remember them with a picture. Or password manager.
Good read: http://lifehacker.com/5937303/your-clever-password-tricks-arent-protecting-you-from-todays-hackers