To make a long story short, there is no autoplay setting in OS X. I was remembering it from OS 9 - but OS 9's autoplay settings do affect CD-ROMs with Carbon autoplay applications on them - talk about confusing! To disable this irritation, launch any Classic application and then in the Classic Apple Menu select the "QuickTime Settings" control panel. In there, select "Autoplay" and uncheck the option to autoplay CD-ROMs. That will stop those pesky auto-launch applications from running.

