SimpleKeys is an excellent app that lets you define hotkeys. A hotkey is usually a combination of keyboard keys that, when pressed, results in a specific action. For example, on Mac OS X, Cmd+Q quits the active application. SimpleKeys is great since it allows you to define a system wide hotkey and it can also restrict a hotkey to a specific application.
Unlike other similar applications out there, SimpleKeys also lets you add several actions to a single hotkey. And the graphical user interface helps a lot in making this as easy as it can be. The interface consists of two panes. On the left pane, you see your hotkeys, and on the right pane, when a hotkey is selected, you see the action or actions that are to be carried out when that hotkey is pressed. When you first create a hotkey, you can choose between different action types, including type text, launch application, paste text, launch a file, run applescript, and more. After you are done adding an action, simply click on the "+" button below the right pane to add another one. All of them will be carried out in the shown order when you press the hotkey.
Finally, SimpleKeys can save you a lot of time by allowing you to assign system-wide and application-specific hotkeys. By the way, it is customizable and very easy to use.