It is a huge mistake to appear weak to a bully, which questions such as, "Would you like your spouse to be treated this way at work?" make you appear.
Often the supervisors are as intimidated by the bullies as the rest of the staff. If that is the case, all you can do is transfer out. Otherwise, do an outstanding job so that no one can criticize your performance. Report to your director exactly what is going on and/or respond in kind to the bully in the form of a sneak attack when least expected, eye-for-an-eye.
You can't back down from a bully or "make nice" or they will continue to bully you. I learned that the hard way by getting fired from one job and having to leave another because I was too nice.
I'm currently in a job where a co-worker is attempting to bully me by staring at me throughout our entire 30 minute lunch break, making comments about "mustache" (I'm female). I was flustered at first. I went to my boss who did nothing. Now I'm turning around and staring back at her and gearing up to start talking about her morbid obesity. She is totally freaked out that I'm staring back at her! That alone has got her flustered!
Now if somebody is dangerous like the other poster brought up, of course I would just have to leave the job like everybody else. But if somebody is just mean-spirited and trying to hurt your feelings, you have to toughen up, stop being nice, grit your teeth, and do and say all the things you were taught were sinful when you were a kid!