"How would Christians observe the birth of Christ, if exchanging presents was not involved?"

I think Christian people observe Christmas in many ways now that don't involve gifts at all. In their Eve services and midnight mass, in reading the words from the Bible that tell the story of not only Christ's birth, but the lesson of his life, and of course in song. This would be there and theirs with or without gifts.

Spaw...Resident Agnostic