My favourite generation overall, Pokemon Black and White (and its sequels) are the climax of the 2D era of Pokémon. The sprites cannot be better made, with the Pokémon jumping around during battle, the music is one of the best of the series and the game had a really nice narrative for a Pokémon game that many still remember fondly. Highly recommend if you want to go back to the early versions of Pokémon without going as far as Gen 1 or 2.