Keyboard Cowboy is a hotkey shortcut manager that is both powerful and easy to use. It can launch applications, switch between them, open url schemes and open both files and folders.

Scopes

You can add scopes to your shortcuts so that they are only available when using a specific application.

Applications

When you bind an application to a hot-key and you execute that command, two things can happen.
If the application is not running, it will launch.
If the application is running it will simply gain focus.

Having "When switching to application, switch to space with open windows for application" enabled in System Preferences will switch Desktop and present the application.

Files & Folders

When binding a hotkey to a file, the file will be opened with the default application that is associated to that filetype.
If you assign a hotkey to a folder, the folder opens in Finder, if you already have that folder open, it will switch Finder window and focus on the selected folder.

URL schemes

Using URL schemes works a lot like using files, it will open with the default assigned application for that specific url scheme.