I'm a sucker for keyboard shortcuts, but if you prefer to use the mouse, here's the perfect app for you: MouseWrangler.
With MouseWrangler you can configure custom mouse movements and make them trigger a specific action to choose from a single keystroke, multiple keystrokes or launching a program. Unfortunately the choice of actions is limited to those three and you can't add new ones.
MouseWrangler lets you create multiple profiles, each of them with multiple gestures. Gestures are very easy to create; you can even train your movements in a special area called Scratchpad. Just remember that you must hold the right mouse button while drawing the gesture, otherwise the program won't recognize it.
There are many positive features in MouseWrangler: it doesn't require installation, is easy to use and works with all programs. On the downside, it's a bit limited regarding actions associated to gestures, and gestures themselves – you even have to enable support for diagonals in the program's configuration options.
With MouseWrangler you can use mouse gestures to trigger diverse actions on your computer.