In the Netherlands taking the Hippocratic Oath is still part of graduating medical school. It reminds doctors of their responsibilities and the vulnerability of their patients.
As a medical graduate myself I appreciated taking the oath, since helping patients and relieving suffering were the main reasons I went into "doctoring" in the first place.
I view the oath as a very personal pledge. You can't force people to act in an ethical or moral way, but you can instill a sense of professionalism and pride in their work. The oath reminds me why I choose to do what I do and helps me direct my way through the ethical maze of modern medicine.