Michael Bovee, over on his Debt Relief and Credit Guides site has published a very good guide for people about how the major creditors are at providing settlements for problem debt.
For example, Bovee revels the best creditor to settle debt with is Chase, and even before the account charges off. He says:
Chase has been settling pre-charge-off credit cards with their card members for between 25% and 40% for years. While there are instances where settlements are higher, they are for predictable reasons.
You can read the full list and details on each creditor, here.