At the risk of sounding cliche, you should be targeting schools which are a good fit for you, not schools which fall in a certain range for GMAT scores. A 680 is a great score and will certainly be in the 80% range for most top business schools, so I would set my sights high and apply to several in the top 10 whose culture and curriculum seem to align with your goals and study preferences. Your challenge will be in the area of diversity, especially if your work experience is in IT or computing, since there are droves of applicants from India with a similar background. If you do happen to fall in this category, you will need to put extra focus on how you can differentiate yourself, especially with the top ten. Good news is, international applications are down this year, so chances should be better, but don't delay, since the first and second round deadlines are fast approaching and offer your best chances of admittance. Good Luck.