This a good thing happended to Indian cricket. Sachin is a great player , but proved that he is not a great leader and have gone into his own shell while he was a captian. good that he refused the captaincy gracefully. Now selectors now have to decide they wanted a new look to the Indian test squad also with sachin refusing and dravid out of the team. Seeing the weakness Saurav had earlier in the test matches, it is not a good idea to give captaincy to him. This leads only 3 names to discuss, Dhoni, Kumble and Lakshman.
So finally in my opinion, make either lakshman or kumble the captain and give Dhoni the vice captaincy.