Passwords are like Bad Medicine.  Tough to remember and leaves a bad taste in your mouth.  Most people have a one or two favorites they modify to satisfy the computers that make them change it.  To remember these passwords, some people have the old standby of the storing the passwords:

• in the drawer
• under the keyboard
• plain view on the monitor
• and all sorts of electronic formats including Excel, Word and web based "helpers"

If you try to avoid this by using something "you can remember", be very aware that passwords less than 7 characters can be hacked in less than one day if not minutes depending on the characters?  Most people using computers use lowercase passwords and sometimes a number.  Once you start using an 8 character password that has uppercase, lowercase and numbers, it increases to nearly 25 days and if you add a symbol, it's over 2 years.

Knowing this, it seems the best move to create a complex password.  This article is not about creating them but storing them.   Security should not be a hassle.  Once it is, people by nature, go around it.  The classic example is the restaurant that puts something in the back door so employees can take cigarette breaks.  Enter Mr. Burglar who then pistol whips all the employess as he clears out the registers.  So, writing down passwords on paper or putting them into an Excel file is the same as that back door being kept open.

Keepass -  is an Open Source application that runs on Windows, Mac and Linux to store your passwords.  It can run from a USB flash and uses a single database file to store the passwords.  Besides storage, it has a ton of neat featues like an easy navigation system, a search function, drag and drop, information about when the password was created an last modified, a space to add notes and more.  It also can generate passwords for you based on a set of rules you can customize.

 Wikipedia - Password Cracking 
Not surprisingly, many users choose weak passwords, usually one related to themselves in some way. Repeated research over some 40 years has demonstrated that around 40% of user-chosen passwords are readily guessable by programs.  Examples of insecure choices include:

• blank (none)
• "password", "passcode", "admin" and the like
• the user's name or login name
• the name of their significant other or another relative
• their birthplace or date of birth
• a pet's name
• automobile licence plate number
• reversing any of the above so "cat1962" becomes "tac1926"
• a row of letters from a standard keyboard layout (qwerty or asdf)
  

Additional Reading
Especially Bad Passwords (Updated 11/5/2007)
How fast can they crack your password?
Microsoft -The Great Debates: Pass Phrases vs. Passwords. Part 1 of 3