Make sure to uninstall Safari AdBlock if you're planning to update to the latest version of Safari (v3.2.1, included in Software Update), because some kind of system conflict can cause all of your apps to crash at launch. If you're experiencing this, you will have to manually uninstall Safari AdBlock by deleting the Safari AdBlock folder in /Library/InputManagers/ This should restore everything to normal.
(Version 0.3.2)