if you are finding that illustrator quits on you when you are using the pathfinder tool, close the appearance pallet, and restart illustrator. this applies to intel macs.
if you need to use the appearance pallet in illustrator, you can open it, but make sure to close it again before you quite illustrator so that it isn't open when illustrator loads.
yeah, nice one sock. I hope that works. I hate how often illustrator crashes and it always happens when I'm playing with smart objects - so I lose all changes.