An even better arrangement is a Magic Trackpad on the left (or non-primary) hand for scrolling and gestures, combined with any comfortable vanilla (almost certainly non-Apple) mouse on your primary hand for pointing/clicking/dragging.
Surprisingly, as a right-handed person, I found I gained ambidextrous ability to use a trackpad with either hand very quickly.
Surprisingly, as a right-handed person, I found I gained ambidextrous ability to use a trackpad with either hand very quickly.