Like Jeff, I also use a Logitech mouse on my Macbook Pro and it works perfectly.
Having a scroll wheel gives me a tactical feedback without any need to look at the mouse like it would be the case with a Magic Mouse (MM), using MagicPrefs. I know, I have a Magic Mouse and a Mighty Mouse on my iMac and found the later to be better then the MM with SketchUp.
As for using the trackpad, nothing precludes you from using fingers from both hands. I found that I can press the ctrl key with my left hand ring finger, the cmd key with my left hand index finger and press the trackpad with my thumb for Orbit and easily add the left hand pinky finger for pan. This leaves my right hand index finger free to move on the track pad to actually orbit and pan. Releasing the keys and adding my middle finger to the index finger of the right hand allows me to zoom.
Good fingers gymnastic indeed but useful when I feel to lazy to get my mouse when I have just a quick job to do with SU.