I've had the Apple Magic Mouse for some time. When I first played with it in the store it was completely underwhelming. I was sorely dissapointed in it's native functionality. No 'Magic' at all.
The real magic comes from a third party application called "Better Touch Tool". It allows fully customizable multi-finger clicks and gestures to do [almost] anything imaginable. It's truly "Magic" for the Magic Mouse.
What's even better is the "Magic" in "Better Touch Tool" is available to all, even those without the Magic mouse. It has custom gestures for the Touch Pad as well as many keyboard commands that have nothing to do with the touch pad nor magic mouse.
The greatest piece of magic from yesterday's update to this application is that it adds "Snap" capability touted by Windows 7. The Snap capability on the Mac allows the user to drag the top bar of a window to the edge of the screen and it will 'snap' to exactly half screen width and full screen height.
Here's why this is so magical for me. I use the Matrox TrippleHead2Go hardware which turns two (yes, 2 and possibly 3 smaller ones) external monitors into one virtual monitor so that I can have two 20" monitors next to my MacBook Pro. It's really nice. The one issue is that it is virtually "one" monitor 11" high and 36" wide. It can me a pain to maximize windows in each monitor every time I'm plugged in. Now, with the updated Better Touch Tool with 'Snap' it's a breeze. Drag the top bar of the window to the left edge, and it snaps to it's half (exactly one monitor or the duo) and drag another window to the right edge and it snaps to the right half. SWEETNESS!
That is all. Carry on.