Ever since I became and Apple user, I stopped using a mouse for good!
The trackpad is much more powerful and versatile than a mouse. Multi gesture features are pretty much useless with a mouse (even the Magic Mouse). I use the built in trackpad on my MacBook all the time and when I'm at my desk, I use the Magic Trackpad exclusively.
I use the Magic Trackpad for video editing, photo editing, text editing, in fact pretty much for everything. I fully adapted to using the trackpad and I love it. When I have to use a mouse at public places or on other computers that I'm forced to use a mouse, I feel like I'm crippled and using an ancient technology.
I mainly use the trackpad for multi finger gestures such as swiping back and forth between the web pages and scrolling, as well as pinch, zoom and rotating using two fingers, or three finger swipes to switch between the full screen applications. I'm so used to one finger tap to "left click", and two fingers tap to "right click" that I sometimes find myself doing a two finger tap when I use a trackpad on a Windows computer. Pretty funny really.
However , in my experience, no trackpad on any Windows machine that I used so far comes close to the fluid implementation of an Apple trackpad fully utilising the multi gesture features of the OS X. A quick look at the properties of the Trackpad under the Systems Preferences will give anyone a pretty good idea of what a capable device a trackpad is.