I'm using a Contour Mouse, largely because it has three buttons, but it also has a scrollwheel that's controlled by the thumb, which seems a much more natural motion to me. I never used the scrollwheel on mice that had it in the traditional place, but I use it all the time now. The mouse is expensive, but I got a free trial. Also, I can almost guarantee that you want the smallest one. Even it is large, and the larger ones are ridiculously enormous.