Here, I'll start. When I was 8 years old, my parents went to a dinner party and plonked me down in front of the host's computer so I'd stay out of their way. The game they booted up to keep me occupied was Space Quest II. Little did they know what impact that would have on me...
It did keep us busy on the fun DOS conversion
I didn't play it until a couple of years ago when I did my video on it. I imagine I would have had a lot more fun with it if I was a kid and had all the time in the world to explore the world. Sadly, my first KQ game was KQ3, which stopped you from having any fun every 2-3 minutes with the sudden appearance of a bossy wizard.
I didn't play that until 18 when I bought the King's Quest collection. I think if that had been my first experience, I wouldn't have ventured into the adventure games world at all.
That being said, I do plan on making an text adventure game along similar lines.