What why would anyone be paranoid enough to cancel their credit card?
You won't have to pay if your credit card is used you know.
Credit card companies are aware of the situation and they would do anything to keep you as one of their clients.
I called my credit card company yesterday to ask about how long it would take to issue me a new card, as well as what other options I might have other than outright canceling my card. Still haven't made up my mind yet.
A couple of years ago I had a fraudulent charge on my credit card. It wasn't a large amount and the credit company was helpful about taking care of it for me, but their investigation took a lot of time and it ended up being more than two months before my account was cleared of the fraudulent purchase.
ASSUMING that credit card info has been stolen from Sony and that it could get into the hands of anyone willing to pay for it, multiple fraudulent purchases or cash withdraws in large amounts could effectively shut down my line of credit for two (or more) months.
So, yeah, I think I'll remain "paranoid" for a while longer.