Magic trackpad vs. Magic mouse?

Five-year-old Mighty Mouse (trackball) is reaching end-of-life, i.e. best efforts to clean scrollball are no longer working. So it's time to replace it with a Magic Mouse or Magic Trackpad. (Tried a non-Apple mouse and did NOT like it). I have Lion installed on my Intel Mac Mini, am ambivalent about it, but feel (for whatever perverse reasons) that I must shrug and go forward and give myself a chance to experience whatever multitouch and gestures provide.

First question: is there a functional difference between what you can do with the magic mouse and the magic trackpad? Does the mouse support all gestures? Or is the trackpad somehow "more multitouch" than the mouse--is their functionality you have with the trackpad that you don't have with the mouse?

Second question: does the trackpad work reasonably well for tasks like drawing and doing simple Photoshop editing, or is the assumption that the trackpad is just for communicating commands to the UI and that you'd have a separate tablet if you wanted to draw?