Love the idea of pokemon being real... If we got all of the death-defying lark that comes with the anime (seriously, how is Ash not dead?!) Otherwise, far too many destruction possibilities outweighing the 'holy crap there's a pokemon in my kitchen' shock and delight!
My pet would be a Nidoking, or maybe a Ponyta, because who wouldn't want a flaming horse torching all of your property right?