The original Ultima for C64. My parents had it when I was very young, and they were having a competition with the couple who lived in the apartment next door to see who could finish it first. I also remember liking the original Defender of the Crown for the NES. It was the only NES game my dad loved to play, and I remember it fondly. I kept it and put it in a frame for him to hang on his wall. My mom and I used to play Bubble Bobble all day sometimes, which is my favorite NES game by far. I guess I was lucky enough to be born right in the middle of the arcade explosion and birth of GOOD console gaming (1985), and my parents were about 20 or so when they had me. As much as they hate to admit it, the fact that they were the game nerds of their generation turned me into a game nerd of my generation.
My parents are fucking rad.