I used to be a one-button zelot as well... until I bought a new iMac last December and had to finally switch from my old Apple Desktop Bus II mouse to the new style USB pill shaped mouse (actually, I sprang extra for the Bluetooth version). That has to be the worst mouse ever designed. It's too small. It doesn't fit up into your palm. It's click is too stiff even on the low resistance setting. And, with the Bluetooth version, you CANNOT lift the mouse and keep it clicked while lifting (i.e. if you 'run out' of mousing space). Horrible, horrible, horrible mouse. Garbage. It was designed with only ONE thing in mind, aesthetics. Functionality never even entered the designers mind.
So, for the first time, I was forced to shop for a third party mouse... and there is no such thing as a single button Bluetooth or wireless mouse. So I was forced to finally make the switch to multiple buttons... which I have been fiercely and religously opposed to for years... over a decade (as long as I've been using a computer). I ended up with the Logitech MX Laser mouse... and wow... what can I say. I LOVE IT!!!!! It fits SO nice in the hand. It tracks on anything as smooth as butter (it can almost track on glass). I programmed the little side buttons for Exposé. I don't have to reach for the keyboard anymore to 'right click'. And the wheel is great. It's amazing.
Honestly, I was so against multi-buttons... but once I got used to this new mouse (8 buttons BTW, plus up, down and left, right scolling)... I could NEVER go back to one button. One button is great for my Mom... but I could never go back. And it's high time Apple joined the party. Now at least we can buy a multi-button mouse that's not grey or beige or microsoft blue. Hopefully they will add some innovative touches too.
My only disappointment with this rumor is that it's going to be optical instead of laser. Laser tracks 20X better than optical. I can use the Laser mouse on my very light colored IKEA desk with almost no wood grain. I can't use an optical on this desk... I need a mouse pad to use an optical.
And I agree that with the Mac mini and all the new people coming to the Mac... you just CAN'T go to market with a one button mouse. No way. 98% of people have probably never used a one button mouse... so it's a hard sell. And it's always been a HUGE source of confusion and derision as well. Thank you Apple. Finally!!! Just PLEASE PLEASE PLEASE don't screw up the ergonomics in an attempt to make the mouse look like a museum piece. It would be nice to have both, beauty AND function, but please don't sacrifice function for beauty like you did with the horrible mice you ship now.