Tim Rowledge wrote:

>Basically, three buttons is a good number for mouse buttons since you
>can hold the mouse with littlefinger and thumb and use three fingers for
>buttons. Assuming of course that the mouse if physically well designed
>and believe me most of them are not. Scrollwheels? Yuck. If you have
>three buttons, use them sensibly.
>
>So, that's the outline of why three buttons are good and why the menu
>should be on the middle button.
>
>  
>
Tim, you're the man!

The first "real" mice I've worked with were ugly as hell (looked like a 
half-sphere with buttons attached to the front) but passed the main 
usability tests:
- they had 3 buttons
- could be held with rounded fingers (your hand grips around the mouse 
instead of resting flat on it)
That was so much easier on the hand than anything else which I met 
afterwards.
Another idiocy which I'll never understand is mouse acceleration. It 
breaks muscle memory, a main factor of mouse usability.
And don't get me started about optical mice! Not the good ones I saw at 
Xerox SIS which would work perfectly well on any structured surface, but 
the crap that became commercially available later... Even relatively new 
(2 yrs) logitech mice have such a jumpy positioning behavior that it's 
almost impossible to accurately select small-font text. Give me a good 
rubber-coated steel ball any time.

Cheers,
Hans-Martin