There's still time if you order from Tiny Prints by tomorrow. That is the absolute last day to use their Super Rush shipping and guarantee delivery by Christmas Day.
Just because you are waiting until the last minute doesn't mean the cards have to be generic or boring. With Tiny Prints, even in the rush, you can take a few moments to personalize the cards. You can upload some pictures, change the font and text, and make your cards stand out, even if they arrive just in time.