I feel like for fighting games you were either indoctrinated by Tekken or Street Fighter. Weirdly enough, I started with Blazblue, because none of my friends wanted to teach me how the hell you actually played Tekken when I was growing up. But yeah, that being said, I'll go with Street Fighter II.

My gateway drug for JRPGs was actually Final Fantasy X; good thing too, because I think that game actually does the best job of explaining the positives and negatives of each character in your party. Final Fantasy VII comes in a close second because there's so many minigames and set pieces to offset the perceived tedium of RPG gameplay.

For 3D platformers, I'm going with Jak and Daxter: The Precursor Legacy. The interconnectedness of the world, combined with the more context sensitive approach to power-ups helps with some of my issues with earlier collect-a-thons.

I think Viewtiful Joe is a great intro to Character Action games. The 2D action makes it harder to feel overwhelmed imo, and there's a greater amount of platforming and puzzle solving than in most CAGs.