You can also look through the (long) Dear Jane Christmas Swap thread to see some beautiful blocks in (mostly) greens, reds, yellows, and off-whites.
And there are a gazillion other sites here and on the internet for idea.
I think it's whatever colors appeal to you. I saw one at a quilt shop in the 1930's pastel prints. Quite a different look from the taupe/brown/tan exchange ones also displayed.