since the first time Aperture crashed after installing 1.5.6 and leopard I have not had any problems and I've edited hundreds of photos. It has been rock solid. So I'm not sure what changed since that first crash and why others continue to see crashes.
Aperture crashed when i selected: Preferences or any export operation. My solution was as suggested, to remove or move all the .colorPickers inside this directory to somewhere else: /Library/ColorPickers/ And Aperture has been running with out any problems after this simple solution.