We usually put up our tree - a real one - on the 22nd or 23rd of December. Then it comes down on January 6th, Old Christmas Day. I do get other decorating done ahead of that time but usually not until the 2nd week or so of December.
I don't like doing it too early because I get tired of it and it loses it specialness if all the Christmas stuff is there for weeks on end.
I do put Christmas music on the player on December 1st. I start with the James Galway CD ( have for about 20 years or more) and then the absolute best Christmas CD ever -- Good News by Kathy Mattea. Just love that CD!