If you use you computer as much as I do then you might want to have a look at this mouse. I believe it is simply the best trackball ever made! Designed for PCs and Mac’s, the new Expert Mouse® employs Kensington’s Diamond Eye™ optical technology for smooth, precise cursor movement. Surrounding the ball, they have a brand new implementation of an award winning Scroll Ring™ that puts scrolling right at your fingertips. More comfortable than ever, the Expert Mouse® even comes with a soft new wrist rest-right in the box! You get all of these great new features along with the same, large ball, exceptional control, and ease-of-use that has set the industry standard for more than 15 years.

My wife got me one for Christmas because its on sell right now. You can find out more by clicking the link below.