From main series, Black and White: you can't find a single bit of the soundtrack that isn't amazing, the story is really good, and generation 5 is the only one with fully animated pixel sprites...
As for spinoff games, it would have to be PMD Explorers of Sky: on top of the incredible story and soundtrack, I'm biased because this is the only version (aside from the obscure Adventure Squad games on Wii) where I can play as Shinx :D
As for spinoff games, it would have to be PMD Explorers of Sky: on top of the incredible story and soundtrack, I'm biased because this is the only version (aside from the obscure Adventure Squad games on Wii) where I can play as Shinx :D