Why should I have to take his last name?

I think that I shouldn't have to change my name. I am already sucssesfull and well known by this name. Also I do not see why it is so expected of a woman to take the mans last name. Me and my fiance have actualy talked about it yet, except back when we just started dating, so I don't really know what his take is. However, every other person I've said somthing about this with just laughed. So what do you think?