If you want an even quicker way of launching a terminal command line window outside of navigating to the Applications menu, selecting Accessories and then clicking on Terminal, then the excellent little Nautilus extension named nautilus-open-terminal is most definitely for you!
To install, simply run:

sudo aptitude install nautilus-open-terminal

The extension will then download and install itself. Once done, you may need to either restart Nautilus or log out and back in again, but once you’re back, you will notice that right clicking on any folder will bring up a newly extended context menu, with the proud little command “Open in Terminal” blinking back at you from close to the bottom of the menu!

Clicking it will then launch a fresh terminal with the path set to that of the folder you clicked on, making it a snap to open a terminal and immediately work within the folder you wanted to!