I had similar hopes for when BofA bought Fleet, but didn't happen. They bought a line of credit I had with MBNA as well. To this extent, BofA seems to treat those who originally were BofA customers a bit better than those of banks it's acquired.

Not sure if this will be the same situation with JP Morgan Chase acquiring WaMu, but I wouldn't get my hopes up. If anything, they will probably raise rates in order to help finance this purchase.