I love the "IBM USB Optical Scroll Travel Wheel Mouse" (search ebay with those terms to see what I mean). $1-2 each (I buy them by the dozen and spread them aro

I love the "IBM USB Optical Scroll Travel Wheel Mouse" (search ebay with those terms to see what I mean). $1-2 each (I buy them by the dozen and spread them around liberally to friends and family; when they wear out (scroll wheel gets sticky or clunky) I just throw them out like a used-up pencil). Wonderful, small, responsive mouse with smooth scrolling. Works on any machine. (I use them with Macs as I'm a fanboi.)