Of the Apple mouses for older Macs, I like any of the "grey ball" ADB II Mouses. The grey balls were nice and heavy and generally tracked well, even when not cleaned regularly. A really nice (though little known) design feature was the locking mechanism for schools. There's a tiny little hole near the cover over the mouse ball. If you push a straightened out paper clip in there, the cover will click around a little further and lock, preventing students from taking the ball out (unless they have a paper clip and know the secret trick).

I loathed the Apple mouses of the same vintage with the little light weight black ball. They seriously suck and you were constantly having to clean the ball. Another stand-out for bad mouse design from Apple is the original iMac mouse AKA "The iPuck". What were Apple thinking!