I read everywhere that open dns are the best dns servers for bsnl broadband ,but it doesnt improve my connection speed much, can anyone suggest a better dns servers for bsnl broadband

open dns is of no use ,its really bad when connecting from india ,dont use it with bsnl broadband...
the right dns servers depends on place to place ,but here is a good one for almost all places
DNS Advantage servers:
156.154.70.1
156.154.71.1
if this is not working chk this article ,and find the best dns servers which works for you :
http://bsnlbroadbandcheats.blogspot.com/2008/12/bsnl-braodband-slow-downs-get-your.html

Far better to just let your router find the best servers. This way if one fails it can switch to another.