Very hard choice for me, I love legendary Pokémon from 1G, 2G and 3G.
So I hesitated, again and again, to finally choose Mew. No, not only because it's super cute. It's one of the Pokémon that intrigued me the most, because actually, we don't know so many things about it. And, I can't forget it in the epic first movie, it was great in it.