The best way to assess chances based entirely on the GMAT is to review the average or median GMAT of each school's incoming class, and see where your score starts to appear (not the top 80%, but literally the average/median GMAT). The breakdown between Q and V is also significant.

There are lots of "good" MBA programs that have average GMATs in the 660, 650 range, and that's where you'd be safest applying with this score. Boston College, Fisher, Kelley etc are all strong schools where you will have a great experience. But if your image of a good business school is limited to the so-called "M-7" schools (H/S/W etc), you most likely would need to break the 700 mark or have some pretty spectacular leadership to differentiate you from others with similar backgrounds but stronger numbers.

Remember, however, that while GMAT can be a deal-breaker, it's not the sole criterion for acceptance. MBA admission at top business schools is a holistic process, and every aspect of your professional, university and community life will come into play. You may have competitive assets you are not yet aware of!

Good luck!
Margaret Strother