I'm pretty paranoid about shredding my credit card receipts and stuff - you'll be surprised how many of those receipts you throw away contain various combinations of
a) your name
b) your full credit card number's sixteen digits
c) your credit card expiry date.
Now I'm sure that visa and mastercard's fraud detection systems are elegant, but is it really necessary to capture all these things on receipts?
Anyway, this article from Wired, about a cybercrook working for the FBI, is only reinforcing my paranoia. Can't imagine, saving and saving so that you can invest for the future, and having that all taken from you like this...