No research quotations, just tell us what are you using and why: Wireless, left hand, right hand, keyboard integrated mousepad, the ibm tip, classic movable or roller ball, ergonomically shaped, dockable for nightly accumulator recharge.

Presently my main is the monster roller ball, never needing cleaning (but i do anyway), plus saving my hurting shoulder not being forced to make micromovements with a very large joint, on the other hand, so i can read and write, with pen. I'm sure in a while i'll abandon that as the thumb will start suffering from blackberritis. I use mouse gestures add on for firefox (available for IE too) for enhanced navigation.