KNote is an advanced and secure note taking program with built-in file management and blogging capabilities. To learn more about KNote, see KNote in action: MP4 or on YouTube (Introduction and How to use the organizer panel).
It's portable (and stealth as far as I tested it) and free for private use. It's big, though, at ~41mb.
Download it here.
It keeps calling home at startup and I don't know how to disable this behavior.