Actually it all depends upon you which service you want....For example if you are able to pay high brokerages then Motilal Oswal is the best and if you want to pay a little medium brokerages then opt for Sharekhan and Angel Broking....Sharekhan's portal are the best but no support for any calls whatsoever but Angel Broking's portal are the worst and their research is very very good. Also, do not go for Karvy....it's the worst of all. And also do not go for SMC, they are unreliable....Sharekhan is the most transparent house.
Hop this helps you !! otherwise you can contact me trhu my email ID: email@example.com