http://www.ilovefreesoftware.com/09/windows/free-notes-organizer-arrange-notes-tree-structure-notexplorer.html

here's one I hadn't seen before, and didn't turn up in a search in the message archives.

It looks like a simple two-paner, and it's free.

Don't know if it has any interesting features, but I'm just posting a link here for anybody who might want to have a closer look.