Nate put together a nice collage of some layered UI work we did back in the late 90s next to a recent ship from Apple:

The webgraphics UI allowed a user to see all 10 titles and hover in to see details.  The time explorer uses a cleaner mapping of y-axis to time, but lacks the the visibility advantages of the wbg design.

Note: I'm pretty proud of the search stack UI, notably as it was a hidden frame AJAXy implementation for IE, fresh after the introduction of innerHTML.