Depends IMHO. If the dress fits perfectly and the accesories, hair, makeup etc are really good, it would probably look really understated and classy, but if the above are off, it might look a bit hit and miss.
Also, it probably depends on the nature of the ball- some things are more formal than others. If the men are likely to be in white tie then definitely not. If it's a very smart affair you might want to consider something a little more formal, but you still dont have to look like a lampshade!