The coolest thing here is the dictionary - double-tap with three fingers. Adding extra dictionaries is not very straight-forward, but go to this guy: http://mac.tashev.info/:
You can link the dictionary with wikipedia (even the bg version of it). It is amazing.
Another very cool thing is the three finger drag.
Screen 2 - smart zoom, but it doesn't work everywhere.
When OS X Lion came out, the three-finger horizontal drag (swipe) was for switching between screens. In the previous versions it was four-finger. In the latest update they went back to four-fingers, since the three-finger swipe is for dragging windows.
I wouldn't trade a macbook just for the trackpad. I stopped using a mouse since my first one. I am so used to it that when I get back to a normal trackpad it looks like I'm back in the stone age.