KeePass is a free open source password manager, which helps you to manage your passwords in a secure way. You can put all your passwords in one database, which is locked with one master key or a key file. So you only have to remember one single master password or select the key file to unlock the whole database. The databases are encrypted using the best and most secure encryption algorithms currently known (AES and Twofish).
Download | Installer
Download | Portable
Note: The listed version needs Microsoft .NET Framework 2.0 or newer. The Classic version available on the Download Page does not, but has less features.