I was scanning through most of the posts but not each and every one, so excuse me if this was already discussed in depth.
The amount of mouse buttons is really not a matter of "less is more" vs. "more is more". It is more about OS design. Windows was designed from the ground up to work with two mouse buttons while the Mac OS was designed to work with one. If you look at most Windows software today (even Office for Mac), you'll notice that apps seem very crippled if you aren't using a mouse with two buttons many options are only accessible via the right-click and there is no way to right-click with the keyboard (please correct me if I'm wrong). On OS X, only the very high end pro apps like Shake require a multi-button mouse. Most apps work perfectly well with a single-button mouse because they were designed to.
An OS that is designed to work with a single-button mouse is fundamentally more usable and easier to use than one that is designed to work with two mouse buttons. From usability's point of view, less is more. The question thus remains, is OS X less productive because it strives for ease-of-use? As we all know (unlike most Windows-users), this is not the case because of the superb and logical keyboard shortcuts in OS X. In addition, OS X supports multi-button mice in the case you prefer to use one.
If Apple will start shipping two-button mice as a standard, it will change the way developers build their apps. Some developers will start taking the Windows approach and hide options behind contextual menus, degrading usability. I think choice is good (and when it comes to mice, OS X gives you all the choices in the world), but Apple should not abandon the superior fundamentals that lie in their OS regarding input devices.
Also, for touch screens and pens an OS that works perfectly with only one button input device is better. Or how do I right-click with my finger? CRTL-clicking is not very intuitive but it does activate your left hand (well, depending on your handedness) to lie on the keyboard which is great for shortcuts anyway. If you have ever observed Windows users they tend to have their left hand on their side instead of on the keyboard (I'm generalizing of course), while many "pro" Mac OS X users actively use both of their hands to control the OS.
Hopefully the two-button mouse will be an option, nothing more. Apple did the right thing when they designed OS X for single-button input devices, and they should never ever give developers an excuse to use contextual menus instead of "thinking different(ly)".
Thanks for reading my first post
