Rhinoplasty can have either a dramatic effect or a subtle effect on the appearance of the nose depending on what techniques are used and depending on the patient's preference. It is possible to correct a crooked nose an make the nostrils appear more symmetric without having to change other features of the nose.
The best rhinoplasty is one which produces a nose that both looks good and functions well. When performed correctly, other people should not be able to tell that your nose has been operated on, but rather they should that it looks natural.
The best way for patient to gain a better understanding of how their nose might look is to visit with a surgeon who uses computer imaging to set the goals for surgery. Recently, 3D rhinoplasty imaging has become available which allows patients to compare their preop picture with a simulated postop picture and look at them from any angle to see how surgery might change their overall appearance. Gaining a better understanding of what the result would look like before undergoing surgery can help make that decision.