For me, the top 3 games are the obvious Mega Man 2 and SMB3, and Zelda 2. And I actually think Zelda 2 is on the same level. I just love how the game is structured with the overworld (exploration) and dungeons (action), the easy but still deep combat, the scale of the game, the fair and enjoyable challenge, the secrets and so on. Its the perfect 8-bit adventure game imo, and its sad the game got such a bad reputation, as I would have loved more games in a similar vein. I guess there is stuff like (the significantly weaker) Gargoyles Quest-series at least.