Ah, Lycus of Yore, but you are using a poltically correct "sensitive" term when you say Merry XMas as you are actually "X-ing" the word "Christ" out of the picture. IMO. "Happy Holidays" may work also.
Actually it is not disrespectful to use the word XMAS.
The "X" is simply shorthand for the Greek word for Christ, "Xristos."