Something you can say about most people who love Pokémon, either the video game, card game, cartoon, manga, or whatever else - they have a favorite Pokémon. It seems strange that you would, in the most objective sense Pokémon are just tools that, in comparison with other role-playing games, are the equivalent of swords, spells, and tools. Would you say they have personality? Yet people identify with their favorite Pokémon. They extend from the utility in the game and create something greater than what is presented in game or through the Pokédex entries.
Honestly, my favorite Pokémon these days tend to be the Dark-types. While the translated-from-Japanese typing actually comes across as Evil-type, I agree with the translators that this isn't a good match. Dark comes closer to indicating that these dudes may use some shady tactics but you can still use them for your altruistic purposes.