Once my sketch is complete, I do some rough color studies. They don't have to be perfect -- just enough for me to get an idea of the colors that I need to work with.
I consulted a few illustrator friends for a critique, and overwhelmingly everyone liked the cool, blue palette the best. The other one didn't read "holiday" to anyone. This made more sense to me anyway, seeing how I didn't want to use the same palette from the angel last year.