Tab View

Not limited to the Finder should work in all applications

Supports icon, list, and column view within tabs

Buttons: far right closes current tab, middle separates current tab into a new window, left creates a new tab

Option double click on a folder to create a new tab

Double clicking on a folder opens the folder within the tab

You can drag the tabs outside the main window to turn it into another window or double click on the tab

Command double clicking on a folder creates a new window

Selecting group windows (from the window menu) creates a parent window, each other window becomes a tab

Title (ex. the current folder that you are in, in this case 'Applications') in the titlebar changes depending on the selected tab which allows the use of the hidden submenu in the middle (activated with a control + click)