The thing my cats like BEST about Christmas is the wrapping paper. After we open presents, we scrunch it down into balls or something bigger, then throw it on the floor in a pile then leave it there for a few days. Since all of my cats are paper chasers, I end up finding paper balls in every room of the house - upstairs and downstairs. It's a paper free-for all for a few days. They also get all of the boxes from the presents strewn around the house.
We also get them new toys (mice, catnip toys and those nerf like golf balls), new window perches, and anything that is just worn out. But I swear they love the paper game the best of all.
Go figure - give a child a present and all they want is the box anyway!