Well for Me ...Bhiku mhatre- Manoj Bajpai Satya , then Nawazuddin siddiqui Gangs of Wasepur, followed by Ajay devgan Malik in Company , after which comes Chandu - Vivek Oberoi in Company , and Finally Sanjay dutt Raghubhai - Vaastav.
I think the best portrayal of a gangster was the famous Bikku Mhare from Satya. There is none yet in Indian Film industry to match Ram Gopal Verma's master stroke of Bikku - It is the ultimate