My choice of person would be Mallow. I'd like to live in the clouds, be a prince, a nimbusian and attack with lightning matters. Cool!
My second choice would be Yoshi, because he's a super-happy cool dinosaur that lives in nature, and takes vacations.
But Mallow is my principal choice.
BTW: My friend says he'd be Watt, because he can send his attacks through all armour.