It depends on how common your last name is. Some transexuals opt to change their last name if they have a really rare last name that could tie them to their old self, however if you have a more common last name, that might not be too big an issue. I myself have a very common last name, so I didn't change it. Also, I'm my parent's only child and I think it would disappoint my father a bit if I didn't carry on his namesake. I happen to like my last name as well. However, I am a different person than you, so I can't really tell you what to do. Different people have different reasons for keeping or changing their last name.