Which one has been your favorite over the years?

Sorry I couldn't fit them all

Pokemon Crystal. It was the first Pokemon game I played and not a single Pokemon game I played after it was even remotely as much fun.

Pokemon 2 for me (Gold, Silver, Crystal)

Yellow - All because of Pikachu.

Pokemon Yellow........Charizard, Blastoise, Venasaur, Dragonite.....etc...

Pokemon Sapphire. It's the best of all time.

Gold.

For most people, I think the one they played first will be their favorite. For me that's red and blue.

Objectively, I'd say Heart Gold and Soul Silver for the amount of content and partially cause I like my Pokemon following me around. I seriously don't get why they didn't put this into other games, even without the Pokewalker.

Red/Blue/Yellow. I don't really have a preference between any of the three. The first Pokemon game I ever played was Blue, and I still have my original save file. I've replayed Red and Yellow countless times. Also, nostalgia has blinded me. I've never felt quite the same as I did when playing Blue for the first time.

You seem to be right^^