Gee4orce's technique (turning the mouse over and rolling the scroll ball vigorously on the mousepad) is the first thing I try when the scrolling action acts up. That fixes the problem about 9 times out of 10 for me. This might be require twice a week or so.

When that fails to fix it, I use a pre-soaked alcholol tab (they come in a box, each 1-inch square tab individually sealed in an envelope). I use the tab to roll the ball around in all directions as needed. This often dredges up some crud that I can wipe off.

I used a Mighty Mouse for the last couple of years on my old iMac G4 800, and these steps have always returned the scroll ball to full functionality. I even purchased a Bluetooth Mighty Mouse to use occasionally with my MacBook, which I purchased last summer.

As for the aluminum keyboard:

I like the keyboard on my MacBook, which as others have noted is pretty similary to the aluminum keyboard. I'm a touch typist, and I also have arthritis in my fingers. I've found that this style keyboard works very well for me. Just about 3 weeks ago I finally retired my trusty old iMac G4 800 and replaced it with a new 24-inch iMac. Now I have two Macs with virtually the same keyboard, which is great (I still use a Dell keyboard on my PC keyboard at work, too). I also like that fact that I can push the thin keyboard up under the iMac screen on its stand, and still be able to make some use of it, as I frequently have papers or whatever right in front of me on the table.