In 10.5, you can also use a right-click or control-click to get the same hierarchy menu in the Finder or Safari.

This is basic stuff that's been on Macs since whenever...

Since System 6, I have set up my Mac to always open my Finder windows in list view and since OSX, I just select "Always open folders in a new window" from the Finder Preferences General tab.

Then, if I need to open a folder and dismiss the parent folder, I simply Alt/Opt double-click on that folder (also available since System 6). Works better this way.

The only problem that I have seen is that where previously Finder would open a new window and close the parent, 10.5 opens the new folder in the same window and I have to resize the window with the green traffic light button.

If you use full sized windows, including the Toolbar, you can customize the Toolbar to add a "Path" button which shows you how far you've dug into your folder hierarchy. Selecting any folder within that list opens it in a new window.