Today you need to remember many passwords. You need a password for the Windows network logon, your e-mail account, your homepage's ftp password, online passwords (like CodeProject member account), etc. etc. etc. The list is endless. Also, you should use different passwords for each account. Because if you use only one password everywhere and someone gets this password you have a problem... A serious problem. The thief would have access to your e-mail account, homepage, etc.
Perhaps you wonder why I decided to make it open-source. The answer is relatively simple: in my opinion all software that has something to do with security should be open-source. Here's a quote of Bruce Schneier that sums it up pretty good:
Features - KeePass supports the Advanced Encryption Standard (AES, Rijndael) and the Twofish algorithms to encrypt its password databases. - Both of these ciphers are regarded as very secure by the cryptography community. Banks are using these algorithms for example, too. - Even if you would use all computers in the world to attack one database, decrypting it would take longer than the age of the universe. - Even quantum computers won't help that much. The algorithms are symmetric so its complexity would be reduced a bit, anyway, the sun will go nova before you have decrypted the database. - The complete database is encrypted, not only the password fields. So your usernames, notes, etc. are protected, too. SHA-256 is used as password hash. SHA-256 is a 256-bit cryptographically secure one-way hash function. Your master password is hashed using this algorithm and its output is used as key for the encryption algorithms. - In contrast to many other hashing algorithms, no attacks are known yet against SHA-256. - In-Memory Passwords Protection: Your passwords are encrypted while KeePass is running, so even if Windows caches the - KeePass process to disk, this wouldn't reveal your passwords anyway. - Security-Enhanced Password Edit Controls: KeePass is the first password manager that features security-enhanced password edit controls. None of the available password edit control spies work against these controls. The passwords entered in those controls aren't even visible in the process memory of KeePass.