> The best UIs IMO tend to be those that allow operation with the left hand on the keyboard home row, and the right hand on the mouse.
Which would suck for left handed people.
Which would suck for left handed people.
As for the right, as some other commenters have noted it really isn't that bad to use your non-dominant hand with a mouse. Most of the movement precision comes from the wrist and elbow, rather than finer finger control.