I would like to know some of you fans' favorite retro Pokémon version(s). Mine are Platinum and Emerald because of the Battle Frontiers. It can't be 3ds.
I'd have to go with Pokémon Platinum. It's the Pokémon game I've replayed the most, and I always have a good time with it. I often have a hard time branching outside my favorites in the region though, as most of my teams have Luxray and Staraptor. Pokémon Emerald and, if I can count it, Gale of Darkness are the other two I think of very fondly.
Diamond is my definitive favorite. I played it and pearl the most of any game in the series. Sinnoh has it's issues, but I still consider it my Pokémon home.