When attempting to change a file extension in OS X Finder a warning dialog will appear. This could be annoying if you know what you’re exactly doing. Turn off the extension change dialog with the following command.
10.6
Show hidden files in OS X Finder
Mac OS X Finder does not show hidden (.dot) files and folders. Usually administrator will go in the Terminal and browses those hidden files and folders. This command will display all hidden files and folders.
Show OS X Dashboard Widgets on your Desktop
Enable OS X Dashboard widgets on the desktop, with the F12 or F4 key. After applying the defaults write command activate Dashboard, click on the widget you want to move to your desktop, and while holding the mouse button down, click F12/F4 again.
X-Ray style Quick Look folder preview
This command can be performd in Mac OS X Snow Leopard (10.6) and Lion (10.7) to get folders in Quick Look preview to show up with transparent covers. This option gives you an “x-ray” style view of the icons inside a folder.
Disable Apple TV support in iTunes
Disable support for Apple TV within iTunes 7.1 or above. After applying this command the option ‘Apple TV’ will disappear in the navigation bar and the Advanced menu options.