My cards always have a Christmas message, a Christmas design (e.g. not just a pretty house in the snow)but more importantly, always a scripture somewhere. How can they believe if they do not hear? Once a year I can at least put out something out of God's scripture so I take advantage of that.
When I was in my 20's I sent a lot of the fun stuff (Santa and so on) but after I renewed my commitment to our Lord, I ttake the Christmas season with a little more solemnity.
Christ is the reason for the season, how is it that we have allowed the PC crowd dictate otherwise.