My granddaughter puts hers up beginning of November, and she loves it! Her husband once put up her decorations for her when she had had a bad day at work just to cheer her up, and it worked so well, its their little tradition now to have them up early, but then, watching Q.I. I learned that people used to put up their decorations on the 11th of november, so, maybe she is more 'historically' accurate than most, and the date to take them down used to be the 6th of feb!!!
Its not commercialism that makes my family put their decorations up early, its the feel good spirit and happiness that seeing twinkly lights on a dull morning brings them when they have a day of work ahead, so for that, how can it ever be too early!
And believe me, it never ever seems to take the magic out of Christmas for them!! I always stick to the 1st of december, but maybe next year I'll start mid november too!