CK, you flirt! How did you know that would brighten a girl's day? Mr. Clean... ooh. The possibilities.
As a general rule, guys should not buy his woman an appliance (unless of course, she desires it and can use it in the bedroom), clothes (because her taste is NOT yours), soap package (because that's telling her she stinks) or mere gift certificates (which means you didn't take enough time to shop for her).
So the best Christmas gift is the one that she will appreciate. Like making her breakfast in bed, taking her out on a dinner night, taking the kids off her hands for the time being.
As my husband would say..... "Too high a price to pay" then hands me my gift. At least he's thoughtful enough to put a gift receipt in it so I can exchange it.