I recently switched from a MBP to a Mac Pro, which is better for my usage patterns overall, but the one thing I miss is multi-touch gestures. I am disappointed that the Magic Mouse does not replicate the same gesture standards in use on the MB/MBPs.
I'm guessing that it can only track 2 discreet touch inputs at once, rather than the 4+ found on the laptops.
I guess the problem is that you need to hold the mouse, if you use three finger gestures it would slide all over the place.