While I like the main Pokémon series, they're not my favourite games. However, I absolutely love the Pokémon Mystery Dungeon series. I wouldn't say the gameplay is perfect, but I still thoroughly enjoy it, and the plots are actually good. Don't get me wrong, the main series is good too, but it's quite clearly just a sidebit to the game which is unimportant in the long run.
And, despite the fact you're a talking Pokémon, the games do have their serious moments too, which are some of my favourite parts of the games.
On a side note, I can't get the theme tune out of my head. It's slowly driving me insane.