First Apple said they were switching to Intel processors, and now they introduce a multi-button mouse! It's about time! On top of that, they not only made a 2-button mouse, they made a 4-button mouse (left, right, ball, squeeze) with a scroll ball that can scroll vertically, horizontally, and diagonally. I'm not sure if it will be any good for gaming (most "interesting" mice usually aren't) but it seems pretty cool for standard desktop use.
What puzzles me is why they haven't made this standard equipment on new Macs. The biggest complaint most of my PC-centric friends have about Macs is "NO RIGHT CLICK!!!!!11". Although Apple now makes a mouse that can right-click, the user is still basically in the same crappy position as before: If I want to right-click on my Mac, I need to buy another mouse. Hopefully Apple is just trying to milk some initial cash out of this thing for a few months before bundling it with new Macs. There's really no excuse not to make it standard - this is the perfect mouse for Apple. By default when you plug it in, both main buttons do the same thing, so it retains the "one-button simplicity" Apple seems to think novices require. If you are a more advanced user (anyone who wants a real mouse) you just make a quick trip to the System Preferences to configure all 4 buttons.
I want one... but certainly not for $49! That's a bit much. I'll stick to my el-cheapo Logitech for now.
As a side note, what is it with Apple giving products, well, stupid names recently? iWork? iPod Shuffle? Mighty Mouse???? Someone needs to Think a little less Different...