What's your favorite main series game?

Currently, the main series games are:

Pokémon Red Version
Pokémon Blue Version
Pokémon Yellow Version
Pokémon Gold Version
Pokémon Silver Version
Pokémon Crystal Version
Pokémon Ruby Version
Pokémon Sapphire Version
Pokémon Emerald Version
Pokémon FireRed Version
Pokémon LeafGreen Version
Pokémon Diamond Version
Pokémon Pearl Version
Pokémon Platinum Version
Pokémon HeartGold Version
Pokémon SoulSilver Version
Pokémon Black Version
Pokémon White Version

My favorite would have to be Black and White. They have so many original elements, it's fun!