Hi SDG, thanks for your question.

700 is typically the mark to shoot for, but purely from a GMAT perspective your score is adequate. Let's look at the numbers for the most competitive programs you list:
"¢ Esade - Mean GMAT: 670/ Middle 80% range: 600-770
"¢ Ross - Mean GMAT: 704/ Middle 80% range: 650-750
"¢ Darden - Mean GMAT: 699/ Middle 80% range: 650-740

Your 660 is within the middle 80% range of all the schools, especially Esade. The decision to retake the GMAT really comes down to whether you think you can move the needle (say, 30 points). If yes, then it might be worth it to break 700. If you don't think you can, then spend your time on the essays, where you can really differentiate yourself as a candidate. Another consideration is your GPA, which you did not mention. If it is quite strong, then you might feel less of a need to score high on the GMAT. However, one other factor to consider is that you are from an over-represented demographic (Indian technologists) that tends to score quite well on the GMAT, so your score, while fine if you just look at the school's numbers, may unfortunately be a negative differentiator within your demographic.

You did not mention your post-MBA goals. How do they connect with your past work experience? Is there a logical arc from your past to business school to your future? In addition, how successful have you been at work? Five years and some international experience is good, but the schools want to see solid leadership experience - that you have driven results, shown initiative, been perceived as a leader at work.

In terms of your community engagement, unless there is a truly extraordinary story, your pre-university activities (e.g., football) would not likely come into play. Do you have good (and recent) accomplishments from your Indian Red Cross Society involvement? The more you can draw upon rich experiences from here (and other extracurricular activities) and the workplace that showcase your leadership and initiative, the more effective your essays will be.

On the basis of this limited information, I think Darden and Ross are probably stretch schools for you, but if your experiences translate into strong essays, the other schools you list seem like reasonable choices.

Best of luck!
Brian