"You will be able to pick your favorite Pokémon from your collection to become your buddy, opening up unique in-game rewards and experiences. Buddy Pokémon will appear alongside your Trainer avatar on your profile screen, adding helpful bonuses such as awarding Candy for walking together. You’ll also have the ability to change your Buddy Pokémon at any time."
Sounds great for people like myself, who don't live in urban areas and get a limited number of Pokemon spawns. Maybe I'll finally be able to evolve my starter Charmander. What Pokemon are you going to choose to be your buddy?