First, if you are not keeping up with your current level of payments (i.e., collection accounts, etc.), then most of your credit is already ruined. The bankruptcy might hurt you another 50 - 100 points, but right now, that is probably irrelevant. If you are keeping up with minimum payments, it becomes a moot point since no judge will allow you to file Chapter 7 (and probably not even Chapter 13) if you are able to make minimum payments.
While the Chapter 7 bankruptcy wipes your slate clean (again assuming you can qualify for a Chap. 7), it does stay on your credit report for 7 years which in and of itself becomes a black mark. The only people who will touch you in terms of extending credit will be the "We finance anybody" type places - and those accounts come with 24% annual percentage rates.