Apple's Magic Mouse first came on the scene in 2009. It's the first mouse available for consumers to have multi-touch capabilities similar to the way a trackpad functions on the MacBook Air and MacBook Pro.
The surface of the Magic Mouse is one unbroken plane, curved to fit your fingers. The entire surface depresses to produce a click action, but sensors underneath the surface can differentiate your fingers' position and movement. As a result, you can use the Magic Mouse to left or right-click, scroll in 360 degrees, zoom, pan, and swipe all by making gestures on the top of the mouse. What's more, the Magic Mouse is a totally ambidextrous design, so it'll be as comfortable for a lefty as it is for a righty.
If you don't have an iMac, don't fret. The Magic Mouse is available separately and works with any Mac equipped with Bluetooth and OS X 10.5.8 or later. It costs $69.