I recently started using a MacBook Air and find some of the gestures such as the double click zoom in Safari extremely useful, I'm aware I can zoom normally using cmd - (+) but find the gesture zoom much better. Can I simulate the touchpad or another way to do this on my iMac.
BetterTouchTool does exactly what I was after, you can set keyboard and mouse shortcuts to emulate gestures and a bunch of other stuff. You will also need SteerMouse if you want to map the buttons on your mouse to keystrokes then assign them inside BetterTouchTool to gestures etc.
After some testing it's more of just a zoom not smart zoom but still works quite well; I'm happy enough with it.