Sampath is the best for interest rates
HNB is the best for dollar rates
Both are very good in customer care
http://www.sampath.lk/interestrates.php#FD
Talk to the manager and you might be able to get a special rate.
If you open the FD under a age 55+ person's name (like ur father/mother)
Senior Citizen rate increments might apply (depending on the period)
If you dont have an urge in cash, I recommend putting "pay interest at maturation" since it gives a better interest rate.