On a somewhat related note, a relative works for one of the big banks managing card technology stuff. I asked him a while back why we don't go to the chip-and-pin system that is popular in Europe, it seems like a no-brainer. I'm probably going to screw up some details, but from memory:
He said there were two major challenges - the first is that the PIN is stored with the card. Your bank issues you the card and assign you a PIN. Americans are apparently terrible at remembering random numbers and to change it you have to go in with the card and do an enter-old-pin, enter-new-pin. Given how many cards are in circulation in the US they think that could turn into a logistical nightmare. I think he said that in Europe they are assigned a PIN and people there are generally better at remembering it.
The other problem (and I might not quite remember this right) is that the pin authentication isn't done at the nearest clearing house, it has to go all the way back to the issuing bank (?) and that doesn't happen instantly. He said for the big box stores and the like it could happen almost instantly but for the mom-and-pop places that don't have super fast infrastructure, this authentication process would take time and delay the POS process.