This is the best article I have seen yet on why it is ok for Christians to celebrate Christmas/Easter etc. The only one I don't agree with him on is Halloween, personally I believe we ought to stay away from that one, but he does bring up some very good points about Christmas and Easter. He doesn't use KJB though so you will have to look up the verses in your own Bible.

http://www.familyministries.com/secular_customs.htm