Oops! Forgot to reply to this.
I want to say it's a tie between Dragon Quest II and IV for my favorites in the NES years. DQII was a gratingly difficult game and one of the biggest challenges to overcome in that era of gaming. And DQIV did so many things ahead of its time that few games dared to try, like playing as a different character in each chapter until they all meet up. It was very inventive for its time, and I loved it for that.