If you are using GNOME Shell with the latest Gnome 3 you may be wondering why you cannot Alt+Tab through your running applications. This is especially important since the panel and task bar no longer exists, making switching between applications especially difficult. To enable task switching with Alt+Tab you must configure metacity to support this with gconf-editor.
Hit Alt+F2 and type gconf-editor.
Now navigate to the switch_windows key binding.
apps -> metacity -> global_keybindings -> switch_windows
The default value is set to Disabled. Change this to <Alt>Tab instead. Now exit the editor and task switching should be enabled.
