Er, you technically ask us two different questions in the post and in the title. The title asks which one is most like us, but the post asks which one we'd be if we could. :?
Luckily, the answer to both is the same for me: The
Happy Mask Salesman.
Of all the Zelda characters I can think of, I think he's the one I'm the most like. He's an intelligent person, who looks a lot into history and knows interesting legends like the tale of the Ancient Tribe. He seems to be happy most of the time, but has a nasty temper when it gets brought out. He is inquisitive and explores. He enjoys making people happy. And he's confident in his own abilities; he thought he could handle the power of Majora's Mask without danger, so he sought it out. And he was right, except then it was stolen by the Skull Kid who could not handle its power. All these things are traits I would associate with myself, so I believe him to be the most like me. I guess I have a passing resemblance to him as well.
And as for who I would want to be if I could choose, I'd still pick him. If I was to live in a fantastical world or universe like that of Zelda, I can pretty much guarantee you I'd travel around, seeing the sights, and make a living the best way one can while having that kind of lifestyle: Being a merchant. The life of a wandering merchant who buys up goods and sells them for profit while living in fantasy world sounds amazing.