Coming from OS X, I was pleasantly surprised to learn that Ubuntu has a built in editor for assigning keyboard shortcuts to launch applications, folders, or run scripts.To add a shortcut or change an existing one, navigate to System > Preferences > Keyboard Shorcuts. Hit the "Add" button to create a new shortcut. Use the name field to give your shortcut a unique name in the list. In the command field, type in the name of a script or system application to run. If you're not sure what to enter to launch a program like Google Chrome, use the file browser to navigate to File System > usr > bin and scroll through the until you find the application or script you're looking for. After you've picked your application, click "Apply" and then, in the shortcut list, click "Disabled" to assign a combination of keys to launch your command. You might have to scroll down to the bottom of the list to find your command. I prefer to use the Super button, as it's not usually tied up in other applications. Best to stay away from the Control button with a letter key to avoid launching your favorite instant messenger every time you want to save a file. Example: I use Super + c to launch the Chromium browser.