/Users/jonchris/Library/Preferences/Adobe Illustrator 10/Adobe Illustrator 10.0 Prefs
Is where the pref's are stored.
You can try starting Illustrator with the plug-ins disabled by holding down the left shift button while launching the Application.
Jonf's suggetion of disabling Extensions is a good idea. Simply restart your system wait for the Chime then hold your left shift button down until you see something that says safe boot. Then try and open Illustrator; if it opens you have something causing a system conflict. If not continue troubleshooting using this Q-article