I work a bunch of CAD designers. They use the mouse constantly and are constantly trying different mice of all different flavors (wireless, wired, ergonomic, multi-button cad specific, trackballs) but the favorite by far is a Microsoft Basic Optical Mouse v2.0 (the all black with the gray scroll wheel ones.) They are cheap ($15), reliable, and provide all the functions a basic mouse should including a scroll wheel. I didn't believe them, but when my HP mouse at work quit one of the designers gave a one of theirs until I got a replacement. I now have one on my work computer, and it works so well I bought them for my Macs at home.