Hey, I remember coming up with this idea in the chatroom! XD
Optical mouse. The finish is wearing off where my hand goes. >_< Then again, the mouse was pretty cheap. I have to use a mouse, even with my laptop, because the touch-pad-like one drives me insane. And I have to have the vertical scroller thing on the mouse, too, or I also go insane. I also must have a mouse pad; it makes the mouse work so much better, even with optical.
Better pic of mouse pad later.