Mine would definitely be Crystal just because of how much there was to do in that game. There was the bug catching contests, shiny pokemon, breeding, the cloning glitch, and who could forget the Game Corner. Even if you got bored of training and battling there was still something different to do. Yeah this might seem standard in the games now but when you went from playing Red and Blue as a kid to Crystal, it was a big deal. But enough of my nostalgia, I'm sure the rest of you have your own favorite version you want to talk about.