Believe it or not, some creditors prefer those that have filed bankruptcy, as they are a better credit risk. Think about it, who would you rather lend money to:
Person 1:
income - 40k
debts - 40k
no major assets
can file for bankruptcy at any time.
Person 2 (recently discharged from Ch.7):
income - 40k
debts - 0k
no major assets
cannot file bankruptcy for seven years.
EA:
Many states have a homestead exemption, so the odds of losing the house are minimal, especially if you reaffirm the mortgages. You can either return the cars or reaffirm those debts as well. The other assets (assuming no major trust funds, jewelry, etc.) will more than likely very neatly fit in to one of the many state or federal exemptions. That is where an attorney is very helpful.
As for the credit cards, the best advice would be to stop paying them right now if you are decided on banlruptcy. (I represent several of the major credit card companies.)
The effect on your credit will not be that much different between 1) filing ch. 7 , 2) attempting to settle accounts/consumer credit counseling 3) filing ch. 13. Either way, your credit is tarnished (for a short while), but with 7, you save a lot more money. If your assets wont fit into ch.7, or you need to reaffirm many debts, only then should you really consider ch. 13.
Edit: just to clarify one statment by snow. There are certain obligations which are non dichargable, such as fraud, debts owed to the government, support, et al. Student loans that are guaranteed by the govenment ARE dischargable, but the burden of proof is so high, that they are typically considered non-dischargable. (I represent some of the student loan companies.)