3. Twilight 2000, 1984
So by '84 I was a ten year old, full into GI Joe figures ('84 being the best year for them) and Star Wars. I had some RPG goodness behind me already, not to mention this was the same year Red Dawn came out.
That's when I found Twilight 2000, it was all the roleplaying I had experienced to this point, plus all the guns and paramilitary action that was prevalent at the time. It was kind of the perfect combination at the perfect time.
Twilight 2000 also marks a first in that this was the first roleplaying game I began playing with friends on a regular basis where your character one week was the same one you used the next. This is where the beauty of linked games, a campaign even, began to come to light to me for the first time.