I read DNeb's idea on Joel's page and i think it's actually a nice one.
Basically he wants to be able to say to the program (maybe through right-click and choosing "Memorize" in system tray), for the program to memorize the size and positions of any visible windows.
Then when he wants (from right-click and choosing "Arrange") for the program to take any visible windows that it has previously memorized position and size and restore them to their positions and sizes.
I think this is a really nice idea.
Might I add it would be nice in an advanced version to work with multiple layouts:
1. Be able to save multiple layouts by name (ie it should ask you to name your layout when you click Memorize), and then choose from the right click menu which layout to invoke.
2. Be able to delete layouts.
3. If you really want to be clever, have a double-click find the stored layout with the most matching windows visible and activate that one.
I'm looking forward to this tool, I think it would be useful.