This is your own choice. There are numerous trading platforms available. You need to look for reliability, trust worthy & low brokerage trading platform. My trading platforms are : ICICI Direct & HDFC Securities.
It depends on your requirement....if you are a investor then you may opt for brokers like ICICI direct or HDFC securities, however if you are a hardcore trader with more concern about brokerage rates, then brokers like Zerodha or RKSV. For people looking for better rates with dealer assistance, Religare, India Infoline.