written about all of these applications before. What's interesting is the custom solution that Leo describes. He's created four simple text files -- today, ideas, errands and todo -- which he updates with Quicksilver's "append text" command. Finally, he uses GeekTool to display his files on the desktop.
That's pretty nice; simple and effective (I use Backpack myself). Part of the fun of being a geek is learning how other geeks do things.