There's an easier way to quit. Create a new account with a separate email address (create a fake email address somewhere, use a fake name). Then add all the email addresses from your current account to your new one. When there are no email addresses associated with your account your old account is permanently deleted. You can then remove all your email addresses (except for the initial fake one). You will now have a blank facebook account that's not associated with your name and email address. The whole process takes less than 5 minutes.
Someone should create a web app that does it. Imagine if you could just go to http://quitfacebook.org, enter your username and pw, and it would do what you described. Like a step beyond Greasemonkey.
