I've been using KeePass for the past month or so and I love it.
It stored all my passwords in encrypted form and I use FolderShare to automatically synchronize my passwords with all my machines. I only need to remember one unique password - the one to open KeePass. the rest is inside.
It's got security features as far as the eye can see. Here are some:
- For full security information read this page.
- Password are saved in memory in encrypted form. you can make it "copy" a password and once, pasted, it automatically deletes it from memory (you need to copy it again).
- The application can be automatically locked when minimized or after an amount of time
- It can use a Disk-based key file for extra security - meaning you can only unlock it if you have the physical USB key with you connected to the machine.
- It helps you generate good passwords with nice "randomizer" screens to customize the output.
- You can make passwords expire after a certain period
It's free, and open source. Oh, and it's a nice UI too!