and I can highly recommend Finansbank. I also have an account with Garanti but Finansbank is my bank of choice... prefer their internet banking too. Super staff.
I did a search of all bank interest rates some time ago (posted info on CBF) and discounted any that didn't have the info readily available and easily accessible on-line.
I found that Turkish banks were much more up front about their rates than the overseas banks that are here in Turkey.