In a recent study conducted by Imperva on passwords, the most common hacked or stolen passwords were revealed:
Our recommendation when choosing your password is to use a strong password, and not to use the same password for all online accounts you have (e.g., email, banking, etc.). By "strong" we mean that it contains 6 or more characters and that it contains a combination of numbers, uppercase, lowercase and special characters. Special characters can include: !,@,#,$,*,[,(.
If you are using c4.net as your Email provider, you can change your password at any time using our Webmail system. To do so, once logged into c4.net Webmail, go to Settings > Options. In the top area of the Options screen you will see "Account Information" listed, where you will fill in your Old Password, enter your New Password, confirm the New Password, and then press Save to apply the change.
The full "Consumer Password Worst Practices" report conducted by Imperva can be downloaded at http://www.imperva.com/ld/password_report.asp.