In Mountain Lion, you can choose which columns you want to appear in the Finder window from the Finder View Options window. Note that in order to set this preference, List View or Cover Flow View must be the active view.
To Choose Which Columns to Show:
- Click the Finder icon on the Dock
- Switch to either List View or Cover Flow View.
- Choose View > Show View Options from the menu
Press the ⌘ + J keystroke combination.
- Under the Show Columns area, click the check box next to the columns you wish to display.
- Set any additional options such as text size or icon size, if desired.
- To apply the setting to all Finder windows, click the Use as Defaults button.
- Click the close button on the window when finished
Choose View > Hide View Options from the Finder menu.