How to Eject All External Partitions Quickly?
The only caveat to "quickly ejecting" disks with any reliability is that they will not eject if there are files in use which reside on them. That said, you can force eject disks, but that would not be ideal if files are, in fact, in use.

Easiest way to instantly eject all disks is by invoking an Applescript (could also create a shell script, but Applescript is more easily turned into a one-click application solution). 

So go to your Applescript Editor, paste in the following:

tell application "Finder" to eject (every disk whose ejectable is true and local volume is true and free space is not equal to 0)




and save the script as an application wherever you choose (do NOT use the /tmp folder as illustrated). Add the resulting application to your Dock, and you have a one-click Quick Eject.



Note: the and free space is not equal to 0 portion is so that the script doesn't eject the contents of your CD/DVD drive. Remove that if you would like any inserted disks ejected as well.