I would have to say that a good score is generally considered to be anything above 500, which is the mean. However, the answer to this question does really depend on what type of residency you will be applying to.
I have not talked with very many residency sites. So far a what I have been told is good score is a PASS. Don't get too wrapped up in splitting hairs over a few points. Most residencies just want to know that you can pass boards.
The main factor is enthusiam. If you are enthusiatic about the program, then you are already in good standing. Also, are you someone that other people can stand to be around for 3 to 5 years?