Yeah, leave it up. It's nice to look at. I'm leaving mine up till after New Years. :)
Till the second weekend in Januaray after Orthodox Christmas. That is what I was told anyway. Personally I leave up just cuz' I love it till the then.
I have left them up till valentines day. Just put some hearts on it and presto.....V day tree.
Traditionally it is supposed to be unlucky to leave up Christmas decorations for longer than 12 days.
Haha, good thinking but, no, I don't believe it works that way. But there's no harm in trying, is there? ;-)
Forever because "I Wish It Could Be Christmas Every Day". ;)