No I mean I turn it off and like a day later it'll be back "on" again and my calendar will be flooded with birthdays and my contacts my whole list of FB friends.
I was annoyed by this so I haven't quite followed the scientific method so I don't know if it requires everything here but the last steps of allowing FB access to your cal and contacts is needed to fix the issue. I don't particularly want much from Facebook on my phone and everything here seems to do that for me.
Notification Center (NC):
Turned off Facebook App so it now shows in the "Not in Notification Center" list - doing this will still leave birthdays in the NC for some reason
Facebook App:
Turned off all notifications - I believe Events are the important one here.
iCal:
Now this is where I had the same problem as you - I turned off the facebook reminders and they kept selecting themselves again. I noticed it was if I clicked on anything facebook related...especially those annoying notifications you cant get rid of in the NC.
I fixed both problems by going to System Settings - Facebook - Allow These Apps to Use Your Account -> and turning off Calendar and Contacts
Contacts - This will remove the option in your iCal to select FB
birthdays (hence keeping iCal from turning it back on again) and will remove birthdays from your notifications center.
Calendar - This will remove the option to get FB "Events" from your iCal and will remove FB events from your NC.
I don't want events or birthdays so I will keep them both off. I do like my actual contacts keeping up to date with FB sometimes but it's not work it to have my ical and nc flooded with birthdays. The easiest way I have found to get around this is to periodically temporarily enable contacts, hit the update button and then turn it off again.
One other added benefit I have noticed is that I no longer have the issue with iMessage sending to an FB account instead of their phone number. I used to have this issue when searching for a contact within iMessage (as opposed to clicking the send message from within your address book).
Sorry to bring up the dead, but I figured it's only a month old and this FB integration to me so far has been just about as pleasant as chewing on glass.