QUICKER - EJECT 4 EXTERNAL DRIVES ?

To eject all drives except for the boot drive, open the Terminal utility and run the following command:

diskutil eject /Volumes/*

This will unmount any external drives, disk images, and should remove any optical drives in any attached devices.

If you would like to bind this to a button or hotkey, first create a new automator "Service" workflow, and then set the service to have no input but be available in any application. Then add the "Run Shell Script" action, and change the default "cat" command in it to the one above. Then save the workflow and give it a name like "EjectAll."

Then go to the Keyboard system preferences and in the "Keyboard Shortcuts" section select "Services" and locate the new EjectAll service. Then click the "Add Shortcut" button to assign a hotkey to it.

You can also use the following command, either in addition to or instead of the previous command to unmount all hard drives except for the boot drive:

diskutil unmountDisk /Volumes/*

Note that this will not eject any optical disks, so you can include it after the command above in the workflow to unmount other drives in addition to ejecting.