Exposé Active Screen Corners

If you are not already using Exposé Active Screen Corners, you should. This is my setup:

When I move the mouse to,

the top right corner, all the windows are displayed as thumbnails and I can quickly select the window I want to work in.

the top left corner, all windows move away and I can see just the desktop.

the bottom right corner, I see the only the windows for the currently application being worked on.

the bottom left corner, all the spaces are shown.

If you don't like my setup, you can also specify Dashboard, Start Screen Saver, Disable Screen Saver, and Put Display to Sleep.