KeePass is a light-weight easy-to-use password safe for Windows.
3/5 rating by My Open Source
You can put all your passwords in one database, which is locked with one master key or a key-disk. So you only have to remember one single master password or insert the key-disk to unlock the whole database.
The databases are encrypted using the best and most secure encryption algorithms currently known (AES and Twofish).
Top 5 most frequently downloaded Open Source.
Quality software, as rated by My Open Source.