I'm sure everyone has this problem and it is certainly a big problem for myself, passwords. I realize they can be a pain and a lot of people stick with simple ones or use the same one on many sites.
Bad idea on both accounts, using a easy password is asking to get yourself in trouble. One common attack that hackers use is what is called a dictionary attack, they'll simply keep trying different passwords until they hit the right one AND they know what the most common passwords are people use. How many of you have used "123abc" before, I know you are out there.
Using the same password on different sites also presents issues, if your password gets hacked on one site you are now vulnerable to it being used elsewhere. For example if someone were able to gain access to a database for a forum that uses poor security measures such as storing passwords as plain text then the hacker will now have your password and can try and use it elsewhere. In case you're wondering that isn't the case here, passwords are stored using a one way encryption method. To decrypt you need to know what the password is, once encrypted I can't retrieve it myself unless I intercepted when you login. That brings up another possibility that the person running the site might be less than scrupulous.
To solve these problems you can use a password locker like keepass: http://keepass.info/
Keepass will allow you store all your passwords locally and securely. The file when saved and closed is encrypted, you only need to remember one password to open the file to gain access to the rest of your passwords. From there it's simple right click on the entry to copy the username or password to the clipboard. Keepass also generates passwords up to any length and complexity you want which is essential to good passwords. You can also store notes, files and many other things that might be important for that login.
On a side note you can also use this as "in case something happens" repository. I've given the password for this file to a very trusted relative. With each entry I've left notes so they know what it is and other pertinent information.