The average score for the 2015 version of the SAT is 1500, so any score above that would be considered a good score. The highest possible score for the SAT is 2400, but it is the percentile that matters more than the score itself.
The percentile, provided along with the student's score, shows how the student tested compared to others that year. Fiftieth percentile is considered average. One year 1500 may be the 50th percentile, but if the next year, the fiftieth percentile is a 1600, a good score would have to be more than 1600. Whether a score is considered good also depends on which college the student wants to attend. While a 1700 may be considered good for some schools, Ivy League universities will be looking for much higher scores.