Hey, Derek:
I got a summer 2000 iMac in August that had the Pro Keyboard. I found immediately that my typing speed and accuracy dropped significantly, but I thought over time I would get used to is. (Prior to the iMac I had a Performa with the Apple Design ADB keyboard.) I would hit double letters all the time or miss letters; typing a letter was a bit of an ordeal.
Well, earlier this month I finally acknowledged that I was as "used to" the Pro Keyboard as I ever would be, so I ran out to our local CompUSA and bought the MacAlly iMediaKey, and I have to say, I love it! Immediately my typing accuracy and speed are what they were before, and the keyboard just a good feel and action. In addition, it can control your CD player (moving from track to track as well as controlling volume, mute, eject, etc.).
Some people on the forums love the Pro Keyboard, but for me personally it was not a good fit. I don't know if my large hands just didn't fit the small layout, or if it is more the shallow "key dip" and soft (not crisp) action, but either way I was not happy with it.
I'm thrilled with the MacAlly keyboard!