Is this dress good for a tail holiday party?

It depends how formal this tail party is. This is a beautiful elegant evening dress that is not too formal. However, if most of the other ladies aren't going to be dressing so well, I would suggest something without all the ds. Also, since it is a Christmas party, you may want to wear something warmer, depending on where you live and whether you have to walk downtown to get to this party. Of course, you can always wear a jacket. If you do, though, make sure it matches the dress and doesn't make you look like you couldn't find your dressy coat. Also, be wary of showing too much skin around your co-workers. Don't want to give the wrong impression.