I like how in OS X when I Alt-Tab I can pick a window or icon with a mouse click. I recently figured out how do get Ubuntu to perform in a similar fashion. First we need to install the CompizConfig Settings Manager (yes, you will need to be using compiz for this):
sudo apt-get install compizconfig-settings-manager
Next navigate the system menu to System -> Preferences -> CompizConfig Settings Manager. The app should start so next scroll down to the Window Management section and click on Static Application Switcher. Next click the Behavior tab and the last option will be ‘Allow Mouse Selection‘. Enable that check-box and exit the application.
It’s not quite as nice as OS X – you can only select by clicking, just mousing over won’t make each item the active target, but it’s better than nothing!