This is the second design in The War on Christmas series. Replacing the almost-silhouette of the Nazi soldier with Santa's silhouette was a very obvious choice; after all, he sees you when you're sleeping, etc. I've always thought Santa's omniscience was a little unnerving, and so I was delighted when I ran across the original poster and saw immediately how easy and effective the edit would be. I've seen this poster around, too, so I thought it might have some recognizability for the average person. It also has the advantage of being very stylized, simple, and strong.
I think I will be making a v2 of this design soon. The grey rectangle on the left just begs to be replaced with a candy cane...
This design is available at my Redbubble store. The gallery below shows just a few of the possible options. You can find all of the possible products featuring He's Watching You here.