A good score depends on your desired program and their requirements. The best way to evaluate you score is to contact your desired programs.
It is also helpful to look at average scores of programs. Here's a good article to start with. Additionally, this blog post can give you some average scores based off of your major.
In general, scores above the 75th percentile in either section are good – that’s about a 159 or higher in math and a 157 or higher in verbal. Scores at least one standard deviation from the mean are even better, 160 in math and 159 in verbal. And scores two standard deviations from the mean put you in the top 5%, 166 in math and 165 in verbal, at which point your GRE score will certainly not be an impediment.
Remember, these are just averages. The best thing to do is talk to people in your desired program :)
Hope that helps :)