I hate managing passwords - so I've started using a program called "password safe" to manage my passwords electronically. It essentially encrypts all of your passwords into a single database file (using the twofish encryption algorithm). Note that all of these implementations are compatible with the same password safe database file (which you can store on your usb key for example). Just pick a really strong passphrase to protect your database! Original implementation (written by Bruce Schnier):
http://www.schneier.com/passsafe.html
Sourceforge project (windows implementation):
http://passwordsafe.sourceforge.net/
Password Gorilla (OSX/cross platform implementation):
http://www.fpx.de/fp/Software/Gorilla/
Java implementation (another cross platform implementation - not tested):