Well, as a game industry veteran (22 years now....I got my start at Activision as a game tester and a game reviewer for Gamepro...before moving on to Atari, Sega and Sony), I've played a ton of games. I have to say that some of my favorite games were on the NES. I loved many of the ones mentioned here including Contra, Ninja Gaiden (even though it had nothing to do with the arcade game), Bionic Commando....but one of my favorites was one that we made, Die Hard.
It was one of the first games to have a simulated random enemy, health and weapons placement, so items were in different places every time you played it. It also was the first to use line of sight (albeit in a primative top down view) and sound (you could hear footsteps in the next room). It was a lot of fun. I even got to write the game manual. The industry has changed so much. There are days when I definitely miss those simpler times. BBQs, laser tag at night in the building, not nearly as much corporate crap and politics to deal with. Sigh...
Gary
Gary