Facebook won't actually close your account, though. That's the hard part. You have to go thru and delete all your information manually. IF you look on your feed / wall, you can see everything you've done, and you can go and click on it, and delete it. It is a long slow tedious process, and it takes me about 2 hours to do a year.
The normal "cancel my facebook account" procedure that facebook does is to just suspend your account. IT is all there and if you ever log in again, it comes right back. While it is suspended you won't show up on your friends lists, etc, but all your activity is still there.
This makes it really easy & tempting--in the days where just about every webpage has a facebook like button that if you accidentally press will cause you to see the facebook login screen-- to bring your account back.
I went around and around with them over a year ago about this, and their policy is that there is no such thing as "canceling" a facebook account. They keep it ready and waiting for you "for when you want to come back." Thus they will only allow you to "suspend" it. (this policy may have changed given all the high profile facebook quitting in the last year.)
I'm deleting all of the info, when that is done, I'm going to change the real name on the account to asdsrqwer sadfvcawer and then the password to something random and then "Suspend it".