2nd gen is my fave!! I know it's not just nostalgia because I replayed it about two years ago (the original games, not the remakes) and they were just as good. I liked the way you could go back to Kanto and then fight Red with all his like, level 85 Pokemon. It was super intense.

My second fave is the latest gen, X/Y. Real pretty and I had so much fun with it And it had a bunch of new Pokemon in it that I love, like Chespin!