I just got cash. I'm impossible to shop for, since I just buy whatever I want. So about 5 years back we just agreed that I just get cash, since that allows me to buy the stuff I really want, when I get the itch.
My rule is exactly the opposite - I have cash and I can buy anything I want basically, and I can always save for more expensive things.
So the rule is simply - I neither give nor receive cash or gift certificates. That way I get things I may not have known I wanted, or unexpected things. It also brings a lot more fun into unwrapping presents.
