If I'm quiet, what type a person is good to balance me out in a relationship?

Someone in the middle. Not someone who will talk a lot and carry the conversation/relationship, but someone who has the ability to provoke you to speak your mind and be engaged in the conversation. Someone who will stimulate you to be involved and who will create a comfortable environment; one that is conducive for you to be more of an extrovert or to "come out of your shell".