I'm a Christmas girl, through and through.
"Happy Holidays" is fine, and so is "Season's Greetings," but for me it's "Merry Christmas!"
Still, today is Winter Solstice, and it's basically the same mixed-up business. (religions have been "borrowing" gods, holidays, and myths from each other forever, and this is no exception.) From darkness to light! Hope is born! And the cycle continues.
I came across this short article at Scienceblogs with a quick explanation of the astronomy, and, more importantly, pretty pictures of the sun in its various phases. oooooh, purty!