*edit* You should note the reason that they don't require ID is because you can get a CC with any name on it to protect your personal information. Visa and Mastercard both want their cards to be accepted "good as cash", and they go to great lengths to ensure that. I know for certain that after filling out the above link, I've seen "$5 minimum charge", "ID required for credit card", and other signs disappear.
Before someone suggests the "SEE ID" thing - that's invalid, and a merchant is supposed to have you sign the card in front of them. That is because the card acts as your half of the contract, a signature saying "I agree to the terms and conditions of this card." It has nothing to do with identifying you. So, unless you've changed your legal signature to SEE ID, you should probably go sign your cards .