Why was Jesus born in Bethlehem?

I have been asking Twitter why Jesus was born in Bethlehem. I've had a number of replies. hear are a few of them and a few of my own thoughts:

• It was prophesied (this seems to be favorite)
• There was a census
• Joseph and Mary where from the lineage of David
• Mary had just ridden on a donkey along I imagine a bumpy road - if that doesn't induce labor I don't know what will.
• JOSEPH WENT TO PAY HIS TAXES

Just saying. 

So while you do your Christmas shopping remember that the first Christmas happened in Bethlehem because a small entrepreneur went to pay his taxes. I imagine Herod didn't. 

http://www.ethicalconsumer.org/