Are you giving half of a gift? Are batteries not included? Nothing shatters the excitement of Christmas like forgetting the accessories for toys and electronics. Whether your kid's robot needs extra batteries, your new digital camera needs a memory card, or the new flat-screen TV needs an HDMI cable to be hooked up, you don't want to be left disappointed with an incomplete gift. Check out these top gift enhancers to make sure every gift is complete this Christmas.